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

Analysis by Climate Central indicates that carbon pollution significantly increased the likelihood of abnormally warm winter days across the U.S. from December 2023 to February 2024. Approximately 85% of the U.S. population experienced at least one day where warm temperatures were at least twice as likely due to climate change. The Midwest experienced particularly strong climate fingerprints, with Minneapolis showing the largest warm departure from normal temperatures among 487 global cities with populations over 1 million. San Juan, Puerto Rico, recorded the highest number of days influenced by climate change at Climate Shift Index level 2 or higher.

• Between December 2023 and February 2024, approximately 85% of the U.S. population (283 million people) experienced at least one winter day with warm temperatures that were at least two times more likely due to human-caused climate change.
• Of the 247 U.S. cities analyzed, 51% (127 cities) had five or more winter days with a Climate Shift Index (CSI) level 2 or higher, meaning warm average temperatures were at least twice as likely because of climate change.
• The U.S. Midwest experienced significant warming; Minneapolis had the largest departure from normal winter temperatures (10°F warmer than average) among 487 analyzed global cities with populations exceeding 1 million. This regional warmth coincided with near record-low ice cover on the Great Lakes.
• San Juan, Puerto Rico, had the most days influenced by climate change of any U.S. city, with 84 days at CSI level 2 or higher, 65 of which reached level 5 (indicating temperatures would have been virtually impossible without carbon pollution).
• Winter warming has broader ecological and economic implications, including longer allergy and growing seasons, disrupted chill for fruit and nut crops, changes in snowfall and water supplies, and a decrease in home heating demand.

APA

Pershing, A. (2024). Warm Winter Days Boosted by Climate Change in U.S. Cities. Climate Central. https://www.climatecentral.org/climate-matters/2024-us-winter-attribution

Chicago

Pershing, Andrew. Warm Winter Days Boosted by Climate Change in U.S. Cities. Climate Central, 2024. https://www.climatecentral.org/climate-matters/2024-us-winter-attribution.

Wikipedia

{{cite report |last1=Pershing |first1=Andrew |title=Warm Winter Days Boosted by Climate Change in U.S. Cities |publisher=Climate Central |date=7 March 2024 |url=https://www.climatecentral.org/climate-matters/2024-us-winter-attribution |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{pershing2024warm, author = {Pershing, Andrew}, title = {{Warm Winter Days Boosted by Climate Change in U.S. Cities}}, institution = {Climate Central}, year = {2024}, month = mar, url = {https://www.climatecentral.org/climate-matters/2024-us-winter-attribution}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }