Snow has arrived in Chicago! And the first measurable snow of the 2024-2025 season was impressive.
According to the National Weather Service’s Chicago office, 2.9 inches of snow fell at O’Hare International Airport. That makes it the largest measurable snowfall since 2016. And though much of it will melt due to warmer temperatures, the city and suburbs had its first view of a winter wonderland.
What’s the difference between first snowfall and first measurable snowfall?
Weather conditions recorded at O’Hare airport are the benchmark for the city. If there is less than a tenth of an inch observed at O’Hare then that counts as a “trace” amount — even if it doesn’t stick. Whether a trace amount of snow is a “first snow” is up for debate. If a tenth of an inch or more accumulates, then that counts as “measurable.”
How does 2024’s first snowfall compare with recent years?
Halloween 2023 was just the 10th time in local weather history that the first freeze and the first snowfall of the season were achieved on the same calendar day, said Jake Petr, a meteorologist in the National Weather Service’s Chicago office. It’s also just the eighth time snow had fallen in Chicago on Halloween — and only the third time a measurable snowfall has been recorded on Oct. 31.
O’Hare International Airport recorded a trace of snow on Oct. 17, 2022, then its first inch of snow on Nov. 15, 2022.
Snow finally arrived in Chicago on Dec. 28, 2021, making it the second-longest stretch of days between two measurable snowfalls — almost 288 days.
It was also the latest date of a first snowfall in Chicago history going back to 1885, and just the 26th time in the past 136 years that the city had to wait until the final month of the year to experience snow on the ground.
At O’Hare International Airport, the city’s official recording site, 0.01 of an inch was recorded at 12:10 p.m. A total of 1.5 inches fell. March 15, 2021, was the last time more than a trace of snow was reported at the site.
The area’s first measurable snowfall of the 2020 season recorded 0.7 inches of snow at O’Hare International Airport on Nov. 24, 2020, one week later than the city’s average first-snow date.
In 2016, 6.4 inches of snow fell on Dec. 4 — the largest first snowfall since 1905.
Chicago weather: Here’s what’s normal for fall’s first freeze and first snow
Tracking the first measurable snowfall
Looking back at more than 135 years of local weather data, Chicago has experienced its first measurable snow as early as October 12 (in 2006) and as late as December 20 (in 2012). That’s why Nov. 17 is the date of the average first significant snowfall in Chicago. Remember, measurable snowfall is one-tenth of an inch or more on the ground, while anything less is considered a trace amount. The chart below shows the date of the first measurable snowfall for each year since 1885. Amounts are available, by year, beginning in 1905.
Sources: National Weather Service; Tribune reporting and archives
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