Climatologist Brian Brettschneider has analyzed 45 years of meteorological records to track when the first snow typically falls. using data from NOAA's Global Historical Climatology Network, the study provides a high-resolution look at how geography influences winter's onset .
The Rockies and Great Lakes as drivers of seasonal timing
Geography serves as a primary architect for when snow begins to fall across North America. According to the report, the Rocky Mountains act as a corridor that channels cold Canadian air directly into the high Plains, often pushing early snow further south in those regions than in the Midwest at similar latitudes.
The Great Lakes add another layer of complexity to regional snowfall through the phenomenon of lake-effect snow. As reported by the study, when cold autumn fronts move across the relatively warm waters of the lakes, they become heavily laden with moisture. this process tends to trigger early snowfall in Michigan and upstate New York, often weeks before nearby inland locations see their first flakes.
A 3.5-month swing in Dodge City, Kansas
Historical data reveals that the timing of the first snowfall is often highly volatile rather than predictable. In Dodge City, Kansas, NOAA records show that the first snow has arrived anywhere from mid-September to early January over a 65-year period, representing a massive three-and-a-half-month variance.
This volatility is part of a larger, shifting trend in American snowfall patterns. A separate analysis of 50 years of records indicates that roughly two-thirds of U.S. weather stations now receive less total snow than they did in the early 1970s.. However, the trend is not uniform; a little more than a third of stations, particularly those clustered around the Great Lakes, have actually seen their total snowfall increase.
A 90% confidence in a strengthening El Niño for 2026-27
The upcoming winter season may be heavily influenced by a strengthening El Niño pattern, which the NOAA Climate Prediction Center identifies with over 90% confidence. this climatic driver typically creates a split in weather patterns, bringing a wetter and more active storm track to the southern United States while leaving the Pacific Northwest and Northern Rockies in a drier pattern.
Early signs of winter are already appearing at high-elevation locations like Crystal Mountain in Washington and Arapahoe Basin in Colorado. While these recent dustings are not yet skiable, they represent an early arrival for regions that typically do not see their first flakes until late September at the earliest. This stands in contrast to locations like Levi and Ruka in Finnish Lapland, which have already confirmed October openings by relying on snow farmed from the previous year.
Data gaps in the Gulf Coast and Southern California
Significant questions remain regarding the predictability of snow in the southern reaches of the continent. because parts of Texas, Florida, and Southern California experience such infrequent snow events, the report notes that the data cannot produce a reliable median date for these areas.
Furthermore, it remains unclear how much of the recent early snow in places like Boston is a permanent shift versus a temporary anomaly. While some New England towns have seen several early-snow seaons, other coastal towns in the same region have not experienced the same trend, suggesting that the "first snow" is a highly localized event that defies broad regional generalizations.
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