(Some additional analysis added to this post on April 22nd, 2026…Earth Day!)

I received an email asking me about a graph of Teton County, WY temperatures that appeared in an article from High Country News. The email was inquiring as to whether it matched the actual data from our local weather stations.

After briefly studying the graph (seen below), I realized that it was constructed from what I will call contrived data. Call it manipulated, manufactured, homogenized, or whatever term you like, but it is not an honest representation of the actual data from the official weather observing stations in our region.

The first thing that jumped out at me was the graph shows data going all the way back to 1895. Fact is:  there isn’t a single COOP weather station in Teton County Wyoming that has any weather observations prior to 1905!

The data displayed in the graph above from NOAA, for average annual temperatures, does not entirely coincide with the actual data from the long-term records from the Cooperative Weather Observing Stations located throughout Teton County.

Besides the earliest years of data plotted on that graph, all of our local weather stations are missing entire months or years of data, especially prior to the 1950’s, which would exclude those years from being able to calculate an accurate annual mean temperature.

Somehow, NOAA seems to be able to fill in the blanks, regardless of not having any real data to work with. I will explain how they do that bit of hocus-pocus at the end of this post.

A couple of other notes on the above graph: 1) The red “average” line that was added to the NOAA graph  is not an average line, but rather a linear “trend” line. The “median” line shown would be dividing the data set in half, with half of the numbers (years of data) falling below that line and half of them above that line.

A true representation of the average (or the “mean”) temperature for the whole time period would actually be 34.6 degrees. (I’ll provide that plot at the end of this post).

What follows here in this post are plots made from the raw data for the COOP weather stations in Teton County, WY, with some notes about each weather station’s instrumentation.

The Real Data

There are 5 COOP weather stations within Teton County, WY that have longer-term weather records, which are relatively consistent…. Jackson, Moose, Moran, Snake River, & Alta, WY.

There are three other COOP stations within the county… Darwin Ranch, Old Faithful, and Lake Yellowstone, not included here. Darwin’s records only go back as far as 1975. Old Faithful’s weather records prior to 1988 are essentially nonexistent. Lake Yellowstone’s records date back to 1905, but are very sporadic with huge gaps of missing years over the past 120 years.

I will provide the actual data for each of the five main COOP stations, so you can see the contrast between the real temperature observations reported to the NWS from these stations, and the data that you can retrieve from NOAA’s Climate website.

I chose a maximum of 30 missing days in a year as the threshold for calculating as accurately as possible the annual mean temperature. If any year was missing more than 30 days of observations, then it was excluded from the plot.

In other words, any given year that made the cut, could still be missing an entire month’s worth of data. In those cases, if the majority of missing days were in winter months, that year could have a warm bias. If the majority of missing days were in summer months, that year could have a cold bias.

Each station’s data will be displayed below in a graph, with a 5-year running mean (black line) overlay. Take that with a grain of salt for stations that have long stretches of missing years of data.

To see how many missing days there were for each year, I have provided a link to PDF’s for each station that contains a table of the missing days count for each year.

1) Jackson, WY Mean Annual Temperature graph:

Jackson’s earliest year with complete data is 1905, with a huge gap after that until the late 1930’s and into the 1940’s, and many other missing years after that in the 1990’s to early 2000’s. Jackson used Liquid-in-Glass (LIG) thermometers for daily readings until March 2002, when it changed to digital (MMTS).

Link to PDF of data: JACKSON

2) Moose, WY Mean Annual Temperature graph:

Moose data only goes back to 1959. Prior to that, from 1935 to 1959, the COOP station was located at Beaver Creek, near the Taggart Lake Trailhead. The Moose station moved short distances several times after 1959, until it was relocated to near the new Visitor Center in July 2018. It was at that time that the station switched from LIG to digital thermometers. The Moose weather station stopped taking temperature readings in early 2024 due to technical problems with the new instrumentation (Nimbus).

You can read more about the Moose station’s thermometer issues in a previous blog post: Temperatures & Thermometers

Link to PDF of data: MOOSE

3) Moran, WY Mean Annual Temperature graph:

Moran has the most continuous temperature record in Teton County, dating back to 1914. Unfortunately, its location was moved in 1954, from an open area near river level, to higher ground in a more wooded area. The biggest effect this had was on raising the overnight low temperatures. But, you can still see the jump on the annual average temperature graph that occurred in the mid-50’s, with temps relatively steady after that. Moran used LIG thermometers until May 1999, then switched to digital.

You can read more about Moran’s other thermometer issues in a previous Blog post:
Teton Park nights are warmer…

Link to PDF of data: MORAN

4) Snake River, WY Mean Annual Temperature graph:

The Snake River weather station is located at the South Gate of Yellowstone National Park. It’s earliest observations date back to 1906, but the first complete years of data were 1910 to 1913. Followed by a long stretch of missing years from 1915 to the early 1930’s. Other big chunks of time are missing after that. In September of 1998 it switched to digital (MMTS), and in 2018 switched again to a different type of automated digital thermometer (Nimbus).

Link to PDF of data: SNAKE RIVER

5) Alta, WY Mean Annual Temperature graph:

Located the West side of the Tetons, but still in Teton County, WY, the Alta weather station has it’s earliest readings in 1910, with intermittent observations for several years during the 1920’s, 1940’s, 1970’s, and a few in the early 2000’s. The Alta station switched from LIG to a digital thermometer in September 1986. In April 2017 it switched to a different type of digital thermometer (Nimbus).

Link to PDF of data: ALTA

The Hocus-Pocus

So, how does NOAA make their graph look like a continuous record, when we know it is not? They certainly must use all of the real data shown above, but how are they filling in the all the missing years, as well as going back in time to before any official weather observations were taken?

Here is an excerpt from their site explaining their methods:

“Traditionally, climate division values have been computed using the monthly values for all of the Cooperative Observer Network (COOP) stations in each division, which are then averaged to compute divisional monthly temperature and precipitation averages/totals. This is valid for values computed from 1931-2013. For the 1895-1930 period, statewide values were computed directly from stations within each state. Divisional values for this early period were computed using a regression technique against the statewide values (Guttman and Quayle, 1996).”

In other words, they fudged it.

You can get their full explanation of methods here: NCEI Climate Divisions

Follow the Trends

If you scroll back through the graphs of the real data and try to follow the 5-year running means (black lines) across the clustered time periods that have minimal missing data, then you can more clearly visualize that the peaks of the warmest temps are all within one or two degrees Fahrenheit.

JACKSON’S peak in the last 10 years is within a degree of the peaks in the 1950’s.

MOOSE’S latest peak is within 2 degrees of the peaks in the 1970’s. No data prior to 1959 and a major change in location and instrumentation in 2018. Again, you can read my analysis of that station’s data here:Temperatures & Thermometers

MORAN’S most recent peak is actually lower than peaks in the 1980’s & 90’s, and within a degree of peaks in the 1960’s. (As mentioned, prior to the mid-1950s, Moran’s weather station was in a different location).

SNAKE RIVER’S peak from the last 10 years is not significantly different from other peaks in its historical record, considering the scarcity of consistent historical data,

ALTA’S most recent peak is less than 1 degree Fahrenheit higher than the max peak in the 1960’s.

You can call that 1 to 2 degree Fahrenheit change “moderately” warmer instead of “slightly” warmer

One last thing you may not have considered is the change in instrumentation over the last 10 to 20 years or so, from LIG to Digital thermometers. Digital thermometers can register temperature changes more instantaneously than much slower LIG thermometers. For both maximum & minimum temps.

For comparison, below is NOAA’s  graph of Annual Average (Mean) Temperature for Teton County, WY, which I generated from NOAA’s website: NCEI County Time Series

I also had NOAA’s site generate a mean temperature line for the whole time period, from 1895 -2025, which came out to be 34.6 degrees.

Caveat Emptor!

Bottom-line is, the data NOAA is using here is not a genuine representation of our long-term record of temperature,  to the extent it seems they are using data from well outside the Northwest Wyoming region to fill in the blanks. The Question is: from what part of Wyoming? As moost of us know, weather and the climate varies widely across the state, from the Mountains to the Plains.

The graphs look very tidy and complete, but when you dig deeper, you realize much of that data is just made up. Especially the data prior to the 1950’s when there was essentially only one station in Teton County with consistent data, Moran, and that was when the thermometers were located at a lower elevation near the river, giving it a cold bias. (Again, here is what I wrote about the Moran weather station’s history:
Teton Park nights are warmer…).

Factoring in changes in some station locations over the years, along with instrument changes in more recent years, it really makes analyzing the long-term record even more challenging. As a meteorologist, I am not one for accepting what is presented (especially from computer models) without further investigation and confirmation.

If I was not so intimately familiar with our local weather stations and climate records, I would never have suspected the NOAA graphs were as contrived as they are. Close maybe, but no cigar.

That is not to say I would dispute that temperatures are slightly warmer now (or moderately, if you like) than in the early 1900’s — with the exception of  the 1930’s, which throughout most of the western U.S. were decidedly warmer than recent years.

Given what we know is real, versus what is displayed on NOAA’s graph, one must question the validity of the data they used, especially considering the scarcity of data available from the early 1900’s for Teton County.

As Robert Mallet said in the Manual of Scientific Inquiry, back in 1859:
“Nature, rightly questioned, never lies.”

Post by meteorologist Jim Woodmencey.

Jim is the chef meteorologist at MountainWeather.com and has forecast and written about Jackson’s weather for nearly 35 years, and has lived in Teton County, WY since 1982.

Jackson, Wyoming was not the only place in the West that experienced what was perhaps the weirdest winter ever. It wouldn’t matter if you have lived here only a few years or over 50 years, it was undoubtedly the weirdest due to the lack of snow in the valley and the unusually warm temperatures throughout the entire four winter months. To exemplify this winter, I will review Jackson’s weather data from December through March, and highlight all its uncommon stats.

Data presented for the Town of Jackson is from the Jackson Climate Station. Data for the mountains is from the Bridger-Teton National Forest Avalanche Center weather stations at the Jackson Hole Mountain Resort.

Jackson Town Temps

December was warm, but it was not the warmest ever in the Town pf Jackson. The average high temperature in December 2026 was 11 degrees warmer than normal, at 38.3 degrees. That fell short of the record set back in 1933 of 39.3 degrees. The average low temperature in December 2025 was 14 degrees warmer than normal at 21.1 degrees, which was not as warm as December of 1917’s average low of 25 degrees. The mean temperature in December 2025 was 29.7 degrees, again, not as warm as it was in 1917, with a mean temp of 31.1 degrees.

January 2026’s temperatures ran a little closer to normal, with the average high, average low, and mean temperatures all running just a few degrees above the long-term averages. This January’s monthly mean temperature was 18.9 degrees, whereas the warmest January on record was in 1953 with a mean temp for the month of 30.2 degrees.

You can read more about how the first half of winter played out in this blog post:
Unusual 1st Half of Winter 2025-26

Things didn’t get much better for the second half of winter. In February 2026 temperatures ran about 8 to 10 degrees warmer than normal but did not qualify as the warmest February on record. That record still belongs to 1947.  The average high this February was 39.5 degrees, well short of the record 44.2 degrees from 1947. The average low in February 2026 was 17.1 degrees, also shy of the record of 20.1 degrees set in 1947. The mean temperature this February was 28 degrees, also well below the warmest February mean temperature on record of 32 degrees, from February 1947.

March was the real cooker though, and it deserves special acknowledgement.

March was more like April

March 2026 overall was about 10 to 12 degrees warmer than an average March, and it did break some maximum temperature records in town, but not by much. Starting with an average high temperature of 52.7 degrees in town this March, breaking the old record of 52.5 degrees from 1992, by just 2/10ths of a degree.

The average low temperature in March 2026 was 26.7 degrees, which was one-tenth of a degree cooler than the record warmest average minimum temperature of 26.8 degrees from March 2017.

The mean temperature for March 2026 was 39.7 degrees, beating the old record mean temperature from March of 1934 of 39.1 degrees, by six-tenths of a degree.

Relatively speaking, temperatures this past March were warmer than the average temperatures in Jackson for the month of April. The average high in April is 52 degrees, the average low is 24 degrees, and the mean temperature is 38 degrees.

On March 19th, 2026, Jackson hit 70 degrees, tying the record high for March of 70 degrees, set back on March 31st, 2004. On March 20th and 21st, 2026, the official town thermometer hit 71 degrees, establishing a new record high for the month of March.

The table below lists the monthly averages for Winter 2025-26 as compared to the historic averages.

Answering the question, “Was this the warmest winter on record in Jackson?”, is not as simple as you might think.

Looking at the temperature averages for all 4 months combined (December through March) I found too many winters that had incomplete data to support that assumption. In order to qualify, each winter month must have no more than 5 missing days of data. Prior to 2012-13, there were many winters which had 15 or more missing days. Some winters had entire months of data missing.

For example, in the Winter of 1933-34, December had the warmest maximum temperature on record, but too many low temperatures were missing to calculate a monthly mean temperature. During the winter of 1933-34 there were 45 total missing days of data in December through March, mostly low temperature readings in December and January, and there was no data at all for the entire month of February.

It would be safe to say that this December through March was the warmest in the last 14 years. Since 2012-13, all those winters had at most only 1 missing day of temperature readings.

Town Snow & Water

After three winters in a row with above average winter snowfall in the Town of Jackson, this is the first one that was below average, since 2021-22. Total Snowfall in town, for December 2025 through March 2026, was 45.4 inches. That is below the historic average for those four months of 62 inches.

What may surprise you is, this past winter did not have the least amount of snowfall ever in Jackson. December 2014 through March 2015 Jackson only had 43 inches of snowfall. Winter 2012-13 had 38.3 inches. The winter of 1976-77 only had 32 inches of snowfall. And two other winters checked in with a total snowfall less than this one, 1949-50 with 37.6 inches and 1946-47 with 35.6 inches.

What made this winter so bleak was, every time we got some snow in the valley, it either warmed up and melted, or it changed to rain and washed it all away.

The good news coming out of this winter though is that Jackson had a wetter than average winter. With a total of 7.11 inches of precipitation in town for the four months, compared to a historic average of 5.48 inches. It was also wetter than the previous winter, which had a water total of 6.40 inches in 2024-25.

Mountain Snow

The total snowfall this winter at the Rendezvous Bowl weather station near the 9,600-ft. elevation at the Jackson Hole Mountain Resort, for December 2025 through March 2026, was 252 inches. That is 81 percent of the historic average of 311 inches.

Last winter, from December 2024 through March 2025, Rendezvous Bowl had 365 inches of snowfall. In 2023-24 it had 359 inches, and 2022-23 had 443 inches. Winter 2021-22 had 241 inches of total snowfall, which is less than we had this winter.

The settled snow depth at the Rendezvous Bowl station on April 1st, 2026, was 76 inches. The historic average on that date is 104 inches. On April 1st, 2025, it was 114 inches. On April 1st, 2024, it was 116 inches. On April 1st, 2023, it was 137 inches. And on April 1st, 2022, the snow depth was at 71 inches.

As far as the records: April 1, 1997 had the deepest snow depth of the last 50 years, with 156 inches. April 1st, 1977 had the least with 60 inches.

By the way, following a storm during the first couple days of April 2026 the settled snow depth in Rendezvous Bowl was back up to 93 inches on April 3rd, 2026.

After three seasons in a row with colder temps and above average winter snowfall around Jackson Hole, in both the mountains and the valley, I guess you could say maybe we were due for a below average year. Let’s just hope we don’t get three in a row like this one.

Post by meteorologist Jim Woodmencey

Earth’s atmosphere is made up of many different kinds of gas, most are naturally occurring, some are added unnaturally. Some are considered greenhouse gasses, some are not. In this post I will break down the chemical make-up of the atmosphere that surrounds our globe and explain what effect some of these gasses have on temperatures and our weather.

Earth’s Gases

To put the various gases that surround our globe in perspective, Earth’s atmosphere is made up of approximately 78 percent Nitrogen, 21 percent Oxygen, and a little less than 1 percent Argon. None of these are greenhouse gasses and have no direct physical influence on the temperature at the Earth’s surface.

The remainder of the atmosphere is made up of trace amounts of other gases. Several of those trace gases are greenhouse gases, gases that can trap heat.  The main ones are Carbon Dioxide (CO2) and Methane (CH4). CO2 makes up around 0.042 percent of the atmosphere and CH4 accounts for 0.00017 percent. Those are small portions compared to the most abundant greenhouse gas in the atmosphere, which is Water Vapor (H20).

Water Vapor is a variable gas. It’s portion of the total make-up of the atmosphere accounts for between 0.4 percent over very dry areas, like the deserts, to around 4 percent over tropical locales. Water Vapor also accounts for 95 percent of all the greenhouse gases in the atmosphere, making it the largest and most dominant greenhouse gas in our atmosphere.

CO2 vs. H20

Carbon Dioxide has received an unfair reputation for being the main temperature control knob on the planet, whereas it is a small piece of a larger puzzle. CO2 does play an important role in helping to balance temperatures at the Earth’s surface, without CO2 the planet would become uninhabitable.

Approximately 97 percent of the total amount of CO2 in the atmosphere comes from natural sources, mainly from the oceans. Only around 3 percent of the total CO2 comes from unnatural sources. So, the human contribution of C02 to the total amount of C02 currently stands at 0.00126 percent.

C02 that is emitted into the atmosphere does hang around for long periods of time, from both natural and unnatural sources. Luckily, the majority of that gets balanced by CO2 that is absorbed, by plants, oceans, etc.

(Side Note: Learn more about CO2 in an article I wrote in the Jackson Hole News & Guide in May 2022:  How much do you know about Carbon Dioxide?)

Compared to CO2, Water Vapor (H2O) is a much more influential greenhouse gas when it comes to controlling temperatures and weather patterns around the globe. It is also unique in that it can present itself in three different forms: as a gas, a liquid, or a solid. That is, as water vapor, water droplets, or ice crystals.

In the lower levels of the atmosphere, Water Vapor that condenses into water droplets to form clouds becomes our daily thermostat. In the upper levels of the atmosphere Water Vapor in its gaseous form is also capable of regulating temperatures at the Earth’s surface. Let me explain in more detail, as Earth’s heating and cooling system is rather complex.

To compare the power of both gases and their effectiveness as a greenhouse gas, here is what science tells us:

According to NASA’s Earth Observatory, “Because scientists know which wavelengths of energy each greenhouse gas absorbs, and the concentration of the gases in the atmosphere, they can calculate how much each gas contributes to warming the planet. Carbon Dioxide causes about 20 percent of Earth’s greenhouse effect; water vapor accounts for about 50 percent; and clouds account for 25 percent. The rest is caused by small particles or aerosols, and minor greenhouse gases like methane”.

Therefore, H2O accounts for 75 percent of all the warming, making it the undisputed controller of the Earth’s Thermostat!

H2O as the Thermo-regulator

In the lower levels of the atmosphere, when there is less H20 over us, there is less cloud cover. Clear skies during the day allows more shortwave radiation from the sun to reach the Earth’s surface, producing warmer daytime temperatures. The opposite is true at night, clear skies allow more long-wave radiation to escape to space, resulting in cooler overnight temperatures.

When there is more H20 over us, there is more cloud cover. During the day, clouds impede solar radiation from making it to the Earth’s surface, resulting in cooler daytime temperatures. At night, the outgoing long-wave radiation is blocked as it tries to escape to space and — like throwing an extra blanket on your bed at night — the result is warmer overnight temperatures. Most of us knew all that intuitively.

In the upper levels of the atmosphere, where Water Vapor primarily exists in its invisible, gaseous phase, the effects can be even longer lasting than the daily coming and going of clouds that we see in the lower levels of the atmosphere. Making Earth’s heating and cooling system even more complex.

What you may not know, is that in the upper levels of the atmosphere, Water Vapor is a very effective greenhouse contributor. Up there, it primarily exists in its invisible, gaseous phase, or presents as high, thin cirrus clouds made up of tiny ice crystals.

Water Vapor in the very upper levels of the atmosphere allows incoming solar radiation to penetrate through, but it inhibits long-wave radiation from escaping out to space overnight. Under that scenario, daytime highs and overnight lows will be warmer at the Earth’s surface.

The whole picture, as I mentioned is way more complex and kind of looks like this:

One way that humans add more Water Vapor to the upper levels of the atmosphere is from jet exhaust. Those contrails (condensation trails) that you see on certain clear, blue-sky days are from the warm exhaust hitting very cold air and forming ice crystals, which sometimes spread out into a thin cirrus-type cloud cover at 35,000 to 40,000 feet.

Increasing the amount of water vapor in the upper levels of the atmosphere will result in warmer temperatures at the Earth’s surface. Which can also happen naturally. And it did, very recently.

Eruptive Gases

Not much was said initially about the Hunga Tonga-Hunga Ha’apai volcanic eruption that occurred in the South Pacific, near the island of Tonga, on January 15th, 2022. But now we are starting to see the effect it has had on temperatures and the disruption of weather patterns around the globe.

Hunga Tonga was a rare, and extremely large underwater volcanic eruption. Thought to be the largest such underwater volcanic eruption in recorded history. When an undersea volcano erupts it sends more water into the atmosphere, rather than Sulfur Dioxide, like above ground Volcanoes do. It has been estimated that Hunga Tonga injected 3 billion tons of Water Vapor into the sky, all the way up into the stratosphere.

It has also been estimated that this single eruption increased the amount of Water Vapor in the stratosphere by 10 percent. And slowly over the last few years that Water Vapor has been circulating and spreading around the globe.

Watch the videos from the GOES Satellites (Band 9: mid-level water vapor) at the time of the eruption. The reach of Hunga Tonga’s shockwave is impressive!
Click here: Hunga Tonga Eruption Satellite Water Vapor Images 

The graph below shows the spike in Water Vapor in the upper levels of the atmosphere, between 82° North & 82° South Latitude, following the eruption.

This next graph shows the corresponding spike in global temperature in the lower levels of the atmosphere between 2022 and 2024, from Satellite data.

Undersea vs. Above Ground Eruptions

The effect on temperatures and the weather around the globe from an undersea volcanic eruption vs. an above ground eruption are quite different, because of the type of gas each one spews into the atmosphere.

One of the largest above ground volcanic eruptions in history was Mt. Pinatubo, which violently erupted in the Philippines on  June 13th, 1991. It was the second largest volcanic eruption in the 20th Century. Second only to the Novarupta eruption on the Alaskan Peninsula in June of 1912, in what is now part of Katmai National Park.

These types of volcanic eruptions put copious amounts of fine ash particles and various other gases high into the atmosphere, some reaching all the way to the stratosphere. Sulphur Dioxide (SO2) being the dominant gas from this type of eruption. Sulfur Dioxide when combined with water or water vapor converts into Sulfuric Acid, which then forms fine sulfate aerosols. Those aerosols increase the reflection of incoming solar radiation, thus cooling temperatures at the Earth’s surface.

As the ash and gas cloud spreads out and circulates around the globe, this cooling effect can cover a good portion of the globe and linger for several years. Which it did, and it shows in our local climate records. For instance, the Summer of 1993 was the coldest and wettest summer ever recorded in Jackson Hole.

The difference between Hunga Tonga’s eruption and above ground volcanic eruptions like Pinatubo is that undersea volcanic eruptions spew less Sulfur Dioxide into the atmosphere, most of it dissolves in the ocean. It was estimated that Hunga Tonga only spewed about 440,000 tons of SO2 into the atmosphere, versus the 17 megatons from Pinatubo. Negating any significant cooling effect for most of the Planet from the Hunga Tonga eruption.

Final Thoughts

Because you now know that Water Vapor is the most prevalent greenhouse gas in the atmosphere, and that greenhouse gases trap heat, you don’t need to be a rocket scientist to figure out the result should be warmer temperatures.

According to a statement put out by NASA back in August of 2022 about the effects of Hunga Tonga, “The huge amount of water vapor hurled into the atmosphere, as detected by NASA’s Microwave Limb Sounder, could end up temporarily warming Earth’s surface.” And the effects are estimated to last for up to 5 years or longer. Which means we have a least a couple more years to go until all that extra water vapor finally dissipates.

That may explain some of the unusual warmth, and the unusual weather patterns, that we’ve seen around the globe the last couple of years. So, we may have a couple more years to go until that extra water vapor finally dissipates.

Hopefully, if nothing else, this little science lesson has taught you which gas really has control of Earth’s Thermostat.

Post by: meteorologist Jim Woodmencey

The real significance of Groundhog Day, on February 2nd every year, is that it marks the halfway point of the Winter Season. It is the midway point between the Winter Solstice (Dec. 21) and the Spring Equinox (Mar. 20).

Essentially, we have also reached the midway point of the ski season as well. The first half, December and January,  may not have played out exactly as we had wished for, especially for snowfall in the valley. Yet some folks seem ready to write off the whole season already, thinking that a poor first half means we’ll have a bad second half. While others have implied that we’re doomed to have winters just like this, into the future.

Take for instance the  headline on the front page of the February 4th, 2026 edition of the Jackson Hole News and Guide, proclaiming: “Snowpack portends climate future”. Certainly, an attention-grabbing headline that probably raised your snow-anxiety level another notch.

Within the article were some see-I-told-you-so statements from a pair of university professors, climate researchers apparently, who said, “This is all part of the trend”, and,  “Extreme winters like this will become more regular”. Or, “What used to be extreme, is definitely much more normal now”. Quotes like that really tripped my meteorological trigger.

I would contend that Jackson’s winters have always been up and down, and it’s also the extremes of weather that make our averages. As a matter of fact, looking back over the last 50 winters, for just the first half of the winter season (December & January), the two biggest extremes at the Jackson Hole Mountain Resort were in 1976-77, the least snowy, and in 1996-97, which still boasts the record for the snowiest. We haven’t seen any winters that extreme since.

In the latest 25 years, Since 2020, snowfall on the upper mountain has been pretty consistent in December & January. Lower mountain snowfall has fallen below average the last few winters, but that data can be a bit deceiving, as that weather station has been moved to different locations a few times over the last 30 years.

The only thing about this winter so far that could be considered extreme, is the snow depth at the base of the mountain at the end of January 2026, at only 8 inches, that is the shallowest we’ve seen in the last 50 years, on the 31st of January.

The graph below, shows how much snow depths have fluctuated on the upper mountain and at the base at JHMR over time on January 31st, for the last 50 years. That’s just for the first half of the ski season. You may recall the last two winters had slow starts to the first half, then it dumped in February and March.

To believe that the weather during one half of one winter season is proof a long-term trend is unscientific. So, don’t become a “panican” and sell your skis and winter clothes just yet. What we are looking at here is the weather, not climate.

Allow me to explain what caused the weather we had the last few months and then offer a better historical perspective on Jackson Hole’s snow history. Which will reveal similar or worse conditions here in the distant past.

Blocking pattern affected the first half of winter

So far this winter, across most of the Western United States, temperatures have been warmer than normal with below average snowfall amounts due to a persistent weather pattern that started back in November. A very strong Westerly jet stream across the Pacific has been splitting just off the West Coast as it encountered a very large and strong ridge of high pressure.

(You can also read about December’s weather here.)

That ridge created a huge block in the atmosphere, preventing colder storms in the Gulf of Alaska from reaching the West Coast. Like plopping a huge boulder in the middle of the river, causing the water to flow around it.

The shifting position of the ridge determined the kind of weather we got in Jackson. When the ridge axis was positioned just east of us, a Southerly flow aloft was drawing warmer air up from far southern latitudes and moisture from tropical origins. That produced higher than average freezing levels and rain at lower elevations in December and early January.

When the ridge axis was west of us, we’d get a cooler Northerly flow, and dry weather. When the ridge was positioned directly over us, we’d also get dry weather, with temperature inversions, cold in the valley and warmer in the mountains.

At the same time the West was stuck under this ridge, the Eastern United States was enduring an equally large trough of low pressure. That weather pattern produced record breaking cold and snow from the Midwest to the Atlantic Coast. Does that also portend that winters in the East will be like that more regularly? Perhaps we should pack up and move to Vermont next winter.

Snowpack in perspective

As mentioned, the snowpack at higher elevations in the Tetons did fine the first two months of winter this season. At the Rendezvous Bowl weather station, at around the 9,600-ft. elevation, the settled snow depth at the end of January 2026 was 73 inches. Just shy of the average for the last 50 years at that location of 77 inches, and well ahead of last season when it was only at 56 inches deep in the bowl on January 31st, 2025.

It’s the base of the mountain, at the around 6,500-ft. elevation, that was really lacking, with only an 8-inch snow depth on January 31st, 2026, the lowest on record for that date. Last year at the end of January 2025, it was at 24 inches. The historic average snow depth at the base of JHMR on January 31st is 30 inches. The lowest prior to that was in January 1977, with 15 inches on the ground.

The winter of 1976-77 was the worst (i.e. the most extreme) in the history of the JH Mountain Resort. On the upper mountain the snow depth at Rendezvous Bowl on January 31st, 1977, was only 24 inches, the lowest on record for that date.

According to friends who were here that winter, the area didn’t open until January 15th, and the lower mountain was unskiable. This was before they had any snow making. You had to ride the tram up, and the Thunder lift was operating, but you had to download from Tower-3 on the tram to get back to the base. The second half of winter was no better, and the mountain closed by March 15th, 1977.

If that was your first winter in Jackson, you’d be crying more than you are this year. If you hung out for the following winter, the mountain was having a historic first half of winter. By January 31st, 1978, the upper mountain and the base of the mountain saw what would become its second deepest snowpack on record. Second only to January 31st, 1997’s 133-inch snow depth.

( Valentine’s Day update: On February 14th, 2026 the snow depth at Rendezvous Bowl was at 84 inches. The historic average on that date is 85 inches. The Base snow  depth is now up to 15 inches of settled snow, still about half of average, but better than the lowest year, in 2018 the snow was only 10 inches deep at the base.)

Town Snow Depth

At the Town of Jackson Climate Station, the average settled snow depth on the ground during the whole month of January 2026 was 4.2 inches. That’s well short of the long-term average snow depth in January of 11.6 inches.

(Note: That number is calculated using only years when there were no more than 5 missing days of data in the month, to get a more accurate gauge of monthly average snow depth).

There were years that had less snow on the ground during the month of January. In 2018 the average snow depth in town for the month was 3.7 inches. In 1981 it was 2.4 inches. In 1949 it was 2 inches.

There were also plenty of years recently that had deeper average snow depths in January, including: 2023, 2022, 2020, 2019, 2017, and 2016.

Another way to look at it is by comparing the average snow depth on January 31st in town, in 2026 it was at 4 inches on the 31st.  There were three other years for which there are records that had less snow on the ground on that date: 2018 = 1 inch. 2003 = 1 inch. 1931 = 3 inches.

January 2025 Jackson had 9 inches on the ground. The historic average snow depth on January 31st is 14.5 inches.

Town Snowfall

Jackson also recorded 9.1 inches of total snowfall in January 2026, most of which fell in the first 8 days of the month. That total was about half of the long-term average snowfall in January of 18.5 inches. But, it was more than twice as much snow as we received last year, January 2025 only had 4.2 inches of total snowfall for the month.

Looking back at January snowfall totals in town for the five years previous to that, from 2020 to 2024, only one of those was below average. Here is the list: January 2020 had 35.6 inches. January 2021 had 24.1 inches. January 2022 had 15.1 inches. January 2023 had 19.8 inches. January 2024 had 21.9 inches. I guess I fail to see any trend towards extremes here.

Analyzing the available data for monthly snowfall in January, with years that had complete records, there were 18 other January’s in Jackson’s historical record that had less snow than January 2026, dating back to 1931, which only had 3 inches of snowfall in town. January 1962 only 2 inches of snowfall that January in town, and 1992 had the least, with just 1.6 inches of snowfall.

The extremes on the high end happened in the 1960’s, with 56 inches of snowfall in January 1969 and 48 inches in 1967.

Again, using the criteria of only using months with no more than 5 missing days. Which oddly has fewer missing years than the snow depth chart. I suppose some years the daily snowfall was measured, but snow depth was not recorded every day.

Town Water

The Town of Jackson received 1.14 inches of water in January 2026, not radically below the average for January of 1.43 inches. Again, that was better than last year, in January 2025 Jackson only had 0.36 inches of precipitation.

It may seem counter-intuitive, but between 2020 and 2024, when Jackson had those above average snowfalls in January, only 2020 had above average precipitation. That’s because when temperatures are colder, you can yield more inches of snow out of the same amount of water. Which kind of blows the theory that we’re seeing more rain down at low elevations in recent years. This December and early January was certainly the exception, rather than the rule.

Jackson’s total water mount for December 2025 and January 2026 was 4.72 inches. Historic average total precipitation those two months is 2.95 inches. Well above the average, so you can’t call it a dry winter, so far.

January Town Temps

The average high temperature in the Town of Jackson in January 2026 was 29.7 degrees, which is almost 3 degrees warmer than the long-term average of 27 degrees. The average low temperature in January 2026 was 8 degrees, or 4 degrees warmer than the long-term average low for January of 4 degrees.

Last year in January 2025, the average high was 22.6 degrees, or more than 4 degrees colder than normal. And the average low was minus 2.3 degrees, or more than 6 degrees colder than normal. One up, one down.

The mean temperature this January was 18.9 degrees, the average if the average high and low temperature for the month. The historic average mean temperature in January is 15.5 degrees. So overall Jackson was 3.4 degrees warmer than normal.

January 2025, was more than 5 degrees colder than normal, with a mean monthly temperature last January of 10.1 degrees. One colder January, followed by one warmer January. Do you see the trend?  ….Sorry, I’m being sarcastic.

Consistent records of average mean temperatures go back to around 1935, before that the record is more sporadic. The chart below shows Average Mean Temperatures in Jackson for the last 91 years.

In case you weren’t here to experience all of our fluctuations in temperature the last 90 years prior to this one, here are a few highlights:

— In the last 14 years, since January 2013, there have been 6 Januarys with above average mean temperatures and 8 January with below average mean temps in Jackson.

— The warmest, most extreme, January on record was in 1953, with a mean temperature of 30.2 degrees .

— The coldest, most extreme, January was 4 years prior to that, in 1949, with a mean monthly temperature that January of only 0.7 degrees!

January Summary & Comparison

Closing Thoughts

It’s funny to me how a couple of abnormal winter months are suddenly branded as the “new normal”. What about all those recent years with above normal snowfall,  were they not establishing the “new normal” too? What about the years that were warmer or colder than this January? And if we are expecting the weather to become more extreme, will it be more extreme that it was in previous decades, like in the 1930’s, 40’s, 50’s, 60’s, 70’s, 80’s or 90’s?

Our memories of the weather are pretty short. And I have to admit, in the last 15 years or so Jackson has been blessed with some pretty awesome winters, if you gauge winter by snowfall amounts and the quality of the powder skiing. Sub-par conditions seem to have become unacceptable, or at least unrecognizable, based on your mind’s limited data set.

I’ve been fortunate enough to have lived in Jackson for most of the last five decades, and each winter was somewhat different than the one before. Part of my job the last 35 years has been tracking and analyzing Jackson’s weather, and as you can see from these records, there has always been a lot of variability. I can also tell you, some of the biggest swings in the weather occur in the months of December and January. And that is because of the variability of the weather patterns that set up across the Pacific.

My point in all this analysis is that almost every winter in Jackson is different. One unusual winter, or part of a winter, doesn’t define a “new normal” or portend anything into the future. So, expect the ups and downs and the extremes of weather to continue, as they have in the past and certainly will into our climate future.

Post by meteorologist Jim Woodmencey, who has lived in Jackson for 44 years and has forecast and tracked the weather here for 35 years.

The weather we had in Jackson Hole in December 2025 can be summed up with the title of an old Clint Eastwood movie: “The Good, the Bad, and the Ugly”.

Warm temperatures and rain in December are not the norm for Jackson Hole. But unusual weather patterns cause unusual weather, and that is what we had this past month or so, since November, actually.

November 2025 had record warm temperatures and was exceptionally dry. December 2025 only surrendered the dry part, as it became exceptionally wet but remained warm, warmer than any December in recent memory. Nevertheless, this past December was neither the warmest nor the wettest December on record.

The Bad: Valley Temps

Data from the Jackson Climate Station on the north end of town has the longest, most consistent record of weather data in the valley, and it’s what I use for historical comparisons. To begin, the average high temperature in Jackson for the month of December is 29 degrees. December of 2025’s average high temperature for the month was 38.8 degrees, or about 10 degrees warmer than normal.

That fell short of the record for the warmest average high temperature in Jackson in December, by several tenths of a degree. December of 1933 still holds this record with an average maximum temperature of 39.3 degrees.

The long-term average low temperature for December in Jackson is 7 degrees. The average low this past December was 21.9 degrees, or about 15 degrees warmer than normal. You may be surprised to know, that wasn’t even close to the record for the warmest average minimum temperature for the month of December. In 1917 the average low temperature for December was 24.9 degrees.

Perhaps the best gauge of overall warmth, or cold, for a month is the monthly mean temperature, or the average of both the average high and average low temperatures. December 2025’s mean temperature was 30.3 degrees, or 12 degrees warmer than the long-term average mean temperature in December of 18 degrees. But December 2025 did not break the record for the warmest December in Jackson.

Using that metric of mean temperature, the warmest December ever recorded in Jackson was 108 years ago, back in 1917, with a monthly mean temperature of 31.1 degrees.

Cumulative Warm Days and Nights

There were also several days in December 2025 that had high temperatures in the 40’s in town, a total of 16 days. That also fell short of a record, which is still held by December 1933, with a total of 18 days of 40 degrees or warmer.

Unusually warm overnight low temperatures were also present this past December, with a total of 7 days in town with a temperature of 32 degrees or warmer. Not as bad as December of 1917, which had a total of 12 days at or above freezing for overnight lows.

The warmest day of the month was on December 11th, 2025, with a high of 51 degrees. That’s 10 degrees shy of the all-time warmest December temperature of 61 degrees, from December 12th, 1921. However, the low temperature on the morning of December 11th, 2025 was 42 degrees, breaking the old record of 39 degrees on that date, from 2004.

The Ugly: Rain-Snow-Rain

The precipitation this past December came in waves of snow, followed by rain, followed by more snow, which was again washed away by more rain. Making for ugly conditions on the roads and causing a brown Christmas in town, for the first time in 30 years. Not since 1995 had we experienced no snow on the ground in Jackson on Christmas Day.

Total precipitation in the Town of Jackson in December 2025 was 3.58 inches, more than double the average in December of 1.52 inches, but well shy of any records. The wettest December in Jackson was in 1964, with 5.95 inches of precipitation. Two other Decembers broke the 5-inch mark, in 1955 and 1996.

Total snowfall in town in December 2025 was 14.6 inches, compared to an average snowfall in December of 17 inches. Settled snow depths though went from 5 inches on the ground on December 7th, 2025, to no snow on the ground from December 10th to 18th. Then back up to 5 inches on December 19th, and back to zero by December 22nd through the 26th. That marked the first Brown Christmas the Town of Jackson had since 1995, 30 years ago.

December snowfall returned and made a late inning run with 5 inches of snow on the ground by New Year’s Eve. It was a wild “snowler-coaster” ride in the valley this December.

The Good: Mountain Snow

The best thing about December 2025’s weather was the abundance of snow in the mountains. It was truly a tale of two different Decembers, depending on your altitude.

The Rendezvous Bowl weather station at the Jackson Hole Mountain Resort, at around the 9,600-foot elevation, recorded 104 inches of snowfall in December 2025. That’s 127 percent of the average snowfall at that site in December of 82 inches. This December’s snowfall on the upper mountains lies in-between the least amount of December snowfall, 16 inches in 1986, and the most snowfall in December, 225 inches in 1996.

The settled snow depth in Rendezvous Bowl at the end of December 2025 stood at 71 inches, which is the deepest snowpack measured there on December 31st since 2016, when it was at 86 inches. The average snow depth there on December 31st is 58 inches. Last season, it was at 59 inches. The shallowest snow depth recorded at Rendezvous Bowl on December 31st was 16 inches in 1976. The deepest was in 1996, with 114 inches.

So, the good news about December 2025 is that the snowpack in the mountains was plenty fat. Now, if we can just get the weather pattern to change a little, to keep it all snow to the valley floor, we’d really be looking good into the New Year.

Jim is the chief meteorologist at mountainweather.com and has been forecasting the weather in Jackson Hole and the Teton Range for almost 35 years.