Climate Matters•February 19, 2025
Fewer Freezing Nights
KEY CONCEPTS
As our planet warms, the coldest nights of the year are also warming across the U.S., potentially disrupting both the risks and benefits brought by freezing conditions.
Some 210 U.S. locations (91% of 232 analyzed) have seen a drop in the annual number of freezing nights since 1970.
These 210 cities now experience an average of 15 fewer freezing nights than during the early 1970s.
The widespread drop in freezing nights since 1970 is part of a larger trend of especially rapid warming in cool regions and seasons.
These trends are projected to continue with continued heat-trapping pollution mainly from burning coal, oil, and methane gas.
This Climate Matters analysis is based on open access data from the National Oceanic and Atmospheric Administration (NOAA). See Methodology for details.
The coldest time of year
The coldest time of year is upon us, bringing serious risks. When temperatures drop to their annual minimums, home heating costs spike and many struggle to stay safe and warm amid cold weather hazards.
The coldest time of year also plays important roles in maintaining plant, animal, and insect life cycles; recharging snowpack that supplies freshwater; and sustaining snow and ice for winter recreation and related local economies.
But as our planet warms, the coldest nights of the year are also warming across the U.S., potentially disrupting both the risks and benefits brought by freezing conditions.
Fewer freezing nights
To understand how winter warming is affecting the local frequency of freezing, Climate Central analyzed trends in the number of freezing nights each year from 1970 to 2024 for 232 U.S. cities (see Methodology for details).
Of the 232 U.S. cities analyzed, 210 (91%) have experienced a long-term decrease in the annual number of freezing nights since 1970.
These 210 cities now experience an average of 15 fewer freezing nights than during the early 1970s.
The locations that have experienced the largest decreases in the number of nights at or below 32°F are: Reno, Nev. (89 fewer freezing nights); Albuquerque, N.M. (44); El Paso, Texas (41), and Las Cruces, N.M. (40).
Regionally, the largest drops in freezing nights have occurred in the West (17 fewer freezing nights, on average), Northeast, and Southwest (both 16 fewer freezing nights, on average).
The widespread drop in freezing nights since 1970 is part of a larger trend of rapid warming in cool regions and seasons.
The most rapid warming in the U.S. has generally occurred when and where it’s usually the coldest — including at night, in northern regions, and during winter, which is the fastest-warming season for 185 (76%) of 245 U.S. locations analyzed by Climate Central.
Climate change causing fewer freezing nights
Recent Climate Central analysis found that climate change — due primarily to burning oil, coal, and methane gas — has been behind the increase in winter nights above freezing across the Northern Hemisphere over the last 10 years.
In the U.S., 28 states experienced at least one additional week worth of winter days above freezing each year (2015-2024) due to climate change.
Climate models suggest that the coldest times of the year will continue to warm if heat-trapping carbon pollution continues.
Even with moderate levels of emissions, every U.S. state with the exception of Hawaii is projected to experience a drop in days with below-freezing temperatures by 2040, according to analysis from the Climate Impact Lab.
Fewer freezes: cold weather hazards
There are still extremely cold days in a warming world — but often not as cold.
Extreme cold comes with serious risks. Billion-dollar winter storms in the U.S. caused $3.6 billion in damages and at least 60 fatalities in 2024 alone.
A long-term decrease in the number of freezing days and nights may reduce some of the most acute risks of cold exposure among vulnerable populations, including the hundreds of thousands of people experiencing homelessness in the U.S.
With fewer freezing nights, the costs of home heating may also decrease, reducing the economic burden on many households. The total U.S. winter heating degree days have decreased since 1974, likely a factor in the decrease in methane gas usage in homes during winter, together with changes in heating technologies.
Fewer freezes disrupt cold weather benefits
Although fewer freezing days and nights may reduce some of the hazards and costs associated with the coldest times of year, these trends can also have negative consequences for economies and ecosystems that depend on the cold.
Warming during the coldest time of year can disrupt snowfall patterns, which can in turn limit snow-fed water supplies that people, agriculture, and ecosystems rely on throughout the year.
Communities and businesses that rely on winter recreation may find it difficult to maintain snow and ice. That means less lake ice for ice fishing, fewer cross-country ski days, and shorter snowboarding seasons.
A lack of cold can prolong the active season and expand the range for disease-carrying pests such as ticks and mosquitoes.
Yields of high-value fruit crops that require winter chill can also be impacted by a decrease in the number of freezing days and nights.
LOCAL STORY ANGLES
What are the local impacts of extreme cold nights in your state or region?
The EPA reviews trends in cold-related deaths and contributing factors in mortality due to cold temperature extremes. According to a 2024 Climate Central analysis, 23% of the 1,755 weather-related power outages from 2000 to 2023 were caused by winter weather.
Who is most at risk from extreme cold nights in your local area?
Older adults, children, sick individuals, people experiencing homelessness, and pets all face greater risks from extreme winter weather. People with low-incomes who face higher relative home heating costs are also at risk when overnight temperatures drop, and may qualify for home energy assistance programs. Ready.gov provides guidance to prepare and stay safe, and your city or county may have a cold weather emergency plan.
Tools for reporting on winter weather hazards near you:
Criteria for winter storm watches, advisories, and warnings can vary by region so check out your local National Weather Service office. The NWS also provides resources on winter weather safety, wind chill charts, and an explanation of the polar vortex.
FIND EXPERTS
Submit a request to SciLine from the American Association for the Advancement of Science or to the Climate Data Concierge from Columbia University. These free services rapidly connect journalists to relevant scientific experts.
Browse maps of climate experts and services at regional NOAA, USDA, and Department of the Interior offices.
Explore databases such as 500 Women Scientists, BIPOC Climate and Energy Justice PhDs, and Diverse Sources to find and amplify diverse expert voices.
Reach out to your State Climate Office or the nearest Land-Grant University to connect with scientists, educators, and extension staff in your local area.
METHODOLOGY
The annual count of daily minimum temperatures of 32°F or less from 1970 to 2024 was obtained from the Applied Climate Information System, which is developed, maintained, and operated by NOAA’s Regional Climate Centers. Analysis of the change (1970-2024) in annual frequency of freezing nights was based on linear regression and conducted for 232 locations that had at least one day at or below 32°F in at least half the years in the period of analysis.
Data from the following five weather stations was excluded from this analysis due to large data gaps: Bend, Ore.; Hazard, Ky.; Jefferson City, Mo.; Twin Falls, Idaho; and Wheeling, W. Va. Data from 10 additional stations was excluded from this analysis because they don’t meet the freezing frequency threshold (at least one day at or below 32°F in at least half the years in the period of analysis): Ft. Myers, Fla.; Honolulu, Hawaii; Los Angeles, Calif.; Miami, Fla.; Monterey, Calif.; Phoenix, Ariz.; San Diego, San Francisco, and San Juan, Calif.; and West Palm Beach, Fla.
The projected number of days with a minimum temperature below 32°F is a multi-model average obtained from the Climate Impact Lab, which documents their analysis in a detailed methodology.