Winter's first measurable snowfall could arrive in parts of the United States within weeks, according to a newly released Farmers' Almanac first snowfall map. It charts when different regions typically receive their first measurable snow of the season.
The map is based on long-term climate records, which offer a historical timeline of when snow generally begins across the country.
The Lower 48 is divided into five snowfall windows by the new map, ranging from mountain summits where snow can fall as early as September to areas of the South where a whole winter may go by without a discernible flake.
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Where will it snow first according to the map?
The analysis showed that the earliest measurable snowfall usually occurs in September across the highest elevations of the Rockies and northern mountain ranges.
In the month of October, snowfall follows across much of the northern Rockies, northern Plains, Upper Midwest and northern New England. Denver's average first measurable snowfall falls on October 18, according to NWS climate records. However, the city's earliest recorded measurable snowfall came on September 3, 1961, when 4.2 inches fell.
{{/usCountry}}In the month of October, snowfall follows across much of the northern Rockies, northern Plains, Upper Midwest and northern New England. Denver's average first measurable snowfall falls on October 18, according to NWS climate records. However, the city's earliest recorded measurable snowfall came on September 3, 1961, when 4.2 inches fell.
{{/usCountry}}November brings the season's first accumulating snow to much of the Great Lakes, central Rockies and interior Northeast. Minneapolis–St. Paul typically records its first measurable snowfall around November 4, while Buffalo averages November 8.
The Farmers' Almanac also noted that many locations in the southern United States, particularly along the Gulf Coast, may not record measurable snowfall until December or January. Some coastal areas can even go through an entire winter without accumulating at least 0.1 inch of snow, the threshold used by the National Weather Service (NWS) for a measurable snowfall.
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First real snowfall
The Farmers' Almanac also distinguished between three commonly used snowfall milestones. The first flakes refer to snow observed falling without accumulation. A measurable snowfall requires at least 0.1 inches of accumulation. A significant snowfall generally means one inch or more, often enough to affect travel and outdoor activities.
Chicago demonstrates how far apart such dates can be. The city usually experiences measurable snowfall in November, an inch or more later in the season, and its first trace around the end of October.
Moreover, the first snowfall timing also differs from town to town. According to Meteorologists, neighboring communities can experience very different first snowfall dates because of geography and local weather patterns.
Elevation remains one of the biggest factors. Mountain ridges often cool below freezing while nearby valleys stay warm enough for rain. That temperature difference can delay measurable snowfall even across relatively short distances.
Large bodies of water also play a major role. The Great Lakes retain summer warmth well into autumn. When cold air passes over the lakes, it absorbs moisture. This then produces the narrow bands of lake-effect snow downwind. Areas in western New York, northwestern Pennsylvania and parts of Michigan can receive heavy snowfall while nearby towns remain largely snow-free.
The map, hence, cannot answer whether snow will come early this year. The almanac has confirmed that “averages are not forecasts.”