Boulder’s First Measurable Snow: A Climatological Snapshot
Ready or not, snow season is lurking out there somewhere. Maybe you’ve already dusted off the skis, mounted the winter tires, or convinced yourself that buying an Epic Pass counts as meteorological preparedness. Now comes the big question: when will we see our first measurable snowfall of the season? If recent years have taught us anything, it’s that Mother Nature doesn’t always follow the script. We’ve experienced both the earliest and latest first snows on record within the last six years, proving that just about anything is on the table.
Measurable means that officially 0.1″ or more of snow was recorded. As is often the case early in the snow season, a few flakes mix in with rain, or flurries briefly fly, but never stick to the ground. These are instances where a trace of snow has occurred, but wasn’t measurable. There is a huge variation from year-to-year in the date of our first measurable snowfall. The earliest was September 8, 2020, with 1.7″ of snow falling. The latest measurable snow was November 29th of 2025 (last year). That’s a spread of nearly three months! The normal (median) date of our first snow is October 20th.
Here’s how the odds stack up for first snow dates:
- On or before September 21st: 10%
- On or before October 4th: 25%
- On or before October 20th: 50% (MEDIAN)
- On or before October 31st: 75%
- On or before November 14th: 90%
Historically, Boulder sees its first measurable snow in:
- September: 22% of years
- October: 52% of years
- November: 26% of years
And while climate change is reshaping many seasonal norms, Boulder’s first snow trend is relatively flat over the decades.
How Much “First Snow” Typically Falls?
Our first snow is usually just a teaser, more of a frosty hello than a full-on blizzard. Between 1950 and 2017:
- 54% of first snows were under 2.0″
- Only 12% of first snowstorms topped 6.0″
- Average first snow: 3.0″
- Median: 2.0″
Boulder’s Recent First Snows: A Quick Recap
Here’s just a quick review of how our first accumulating snowfall went down over the last seven years — it’s been a wild ride!
2019 – October 10th (3.8″)
Our inaugural accumulating snow in 2019 occurred on October 10th alongside an Arctic Blast surging into the center of the country. The frontal passage in our area was followed by 2 to 3 hours of heavy jet-forced snow bands. Boulder officially recorded 3.8″ of snow from these bands.
Temperatures also dropped like a rock accompanying this first snow. Denver plummeted nearly 70 degrees in just 18 hours, from the 80s one day into the record-setting teens by the following morning. Needless to say, the 2019 growing season came to a rather abrupt end.
2020 – September 8th (1.7″ on first day, 5.7″ storm total; earliest first snow on record)
In 2020, we had our earliest accumulating snowfall on record in Boulder on September 8th — before the first snow contest was even announced that year! This led to an unprecedented “second” snowfall contest taking shape. The first snow record was just one of many obliterated during the highly anomalous Great Labor Day Snowstorm of 2020 in the Front Range!2021 – November 17th (0.3″)
In 2021, the summer and autumn season both were extremely warm and dry in our area. Boulder ended up tying for its second latest ever first snowfall on November 17th — a measly 0.3″ that only accumulated on grassy surfaces following several hours of very light snow overnight. This historically delayed first snow resulted in all of the contest participants being way off. The person who guessed the latest date won the contest by default. After that crazy late first snow, there was only another inch of additional white stuff that fell over the next five weeks which further primed the dry prairie grasses in the lead up to the Marshall Fire tragedy in late December 2021.2022 – October 27th (0.1″)
The first snow in 2022 was a bit of a disappointment with a rain/snow mix occurring during the daytime hours on October 27th. Boulder recorded an absolutely bare minimum first snow with only a dusting sticking on the grass, and that was only in SOME parts of town as temperatures were mostly above freezing. This led to a lot of confusion when we announced that the contest was over, as some people never even saw a snowflake in their location!
2023 – October 28th (0.6″ first day, 6.8″ storm total)
2023 was the most normally-timed first snow for us in recent memory, unfolding only about a week later than usual. However, this first dumping was on the larger side as a cluster of well-forecasted jet-forced snow bands targeted the Denver Metro area with heavy snow for several hours. When it was all said and done, most Front Range cities picked up between 5 and 10″ of snow. Boulder officially recorded a two-day storm total of 6.8″.
2024 – November 4th (0.2″)
2024’s first snow was definitely underwhelming. A messy storm system brought more than half an inch of chilly rain to the city which briefly changed to snow overnight as temperatures dropped to ~33° for a few hours.
A light dusting of snow accumulated on the grass and trees in Boulder (officially 0.2″), but in some areas it completely melted before sunrise, once again causing some confusion for first snow contest entrants!
2025 – November 29th (0.2″, latest first snowfall on record)
Last year’s first flakes arrived about five weeks later than average, and nearly two weeks later than the previous “latest first snow” benchmarks (November 17 in both 2017 and 2021).
A backdoor Arctic front arrived on the morning hours of November 29th, briefly spawning a few snow bands that gave the entire Denver Metro area a light dusting of snow, including Boulder. Temperatures plummeted into the lower 20s as snowflakes fell across the city during the day.
It was beautiful to see the city dusted in white again after a lengthy 223-day snow drought, one calendar day shy of the existing record.
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Contest
So, what’s your best guess for 2026? Will it be an October surprise or a record-setting December late-comer? Will we get just a sloppy coating or a hefty super El Niño dump?
Feel free to enter the BoulderCAST 12th Annual 2026 First Snow Contest HERE. Contest closes Oct 16, 2026 at 11:59 PM. There are prizes. We didn't say good ones.
This is a community poll for the date you think the first MEASURABLE snowfall will occur in Boulder. Those who come closest to the actual date are the winners. For verification, we’ll go off the official Boulder climate station located at the NIST building in south Boulder (FYI, they follow UTC time for date cut-offs — roughly 5PM to 5PM local time). To be crystal clear, if our first snow event crosses over a calendar day break, only the first day’s snow amount will count.