Extreme Weather Toolkit: Snow & Ice

The timing, location, and amount of snowfall is shifting across the U.S. 

The frozen parts of Earth’s surface — including ice sheets, glaciers, sea ice, permafrost, and snow cover — have shrunk over recent decades due to human-caused warming. 

Snow keeps our planet cooler, makes up more than 50% of the runoff that serves as an important component of water supplies in the western U.S., and supports ecosystems, economies, and cultures across the nation. 

Our warming atmosphere holds about 4% more moisture per 1°F of warming. As winters warm, more of that extra moisture now falls as rain instead of snow. Since 1970, annual snowfall has decreased at 64% of 2,041 stations across the contiguous U.S. Moreover, more than 80% of 170 weather stations across the nation are seeing less precipitation falling as snow than they did in the late 1940s.

Decades of shrinking snowpack has reduced snow-derived freshwater in the western U.S. by 15-30% since 1955. These trends are expected to continue as human-caused climate change worsens, with an additional 25% decline in snow-derived freshwater in the region expected by 2050.

The trends in the western U.S. reflect broader patterns: The latest IPCC reports conclude with near certainty that Northern Hemisphere snow cover extent and duration will continue to decrease as our climate continues to warm. Climate models suggest that Northern Hemisphere snow cover will decrease at a rate of -8% per 1.8°F (1°C) of global surface air warming. 

Updated: May 2025

Resources

These resources explore the science, trends, and local impacts of snow & ice in the U.S.

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Report

Lost Winter: Above-freezing days added by climate change

Across the Northern Hemisphere, climate change is causing a significant increase in winter days with minimum temperatures above freezing, otherwise called lost winter days.

Climate Matters

Fastest-Warming Seasons

Winters are warming the fastest in most of the 245 U.S. locations analyzed by Climate Central — but all four seasons are warming, introducing changes that affect health, water supplies, ecosystems, and more.

Climate Matters

Snowfall Trends

Snow keeps our planet cooler, feeds water supplies, and underpins regional economies and cultures. Here’s how snow is changing across the U.S. with our warming climate.

Climate Matters

Warm Winter Days Boosted by Climate Change in U.S. Cities

Carbon pollution drove abnormal warmth this winter in cities across the U.S. — especially in the Midwest and Great Plains.

Climate Matters

Great Lakes Ice

Over the last five decades, the Great Lakes have trended toward less ice, for less time — consistent with global trends in lake ice decline as the planet warms.

Climate Matters

Shifting Snow in the Warming U.S.

Snow keeps our planet cooler, feeds water supplies, and underpins local economies and cultures. We unpack how climate change is affecting snow—and snow-dependent communities—across the U.S.

Climate Matters

Atmospheric Rivers

Atmospheric rivers bring both vital water resources and deadly hazards—especially in the western U.S.

Climate Matters

Shifting Snow in the Warming U.S.

Snow keeps our planet cooler, feeds water supplies, and underpins local economies and cultures. We unpack how climate change is affecting snow—and snow-dependent communities—across the U.S.

Climate Matters

Atmospheric Rivers

Atmospheric rivers bring both vital water resources and deadly hazards—especially in the western U.S.

Climate Matters

Water in the West

This week, we explain how exceptional drought and our warming climate put western water supplies at risk.

Climate Matters

Weather-related Power Outages Rising

Climate change boosts the frequency and intensity of extreme weather that wreaks havoc on the power grid.

Climate Matters

Chances of a White Christmas

In the midst of the festive season, see the historical odds of snowfall on December 25 — and how they’re changing as the planet warms.