Monthly Attribution Overview – August 2025

August 2025 in the United States was generally cooler than normal, with an average anomaly of -0.5°F across 196 cities, though 189 of those cities have shown long-term August warming trends since 1970. Despite the monthly average, 27 cities experienced at least two weeks of Climate Shift Index (CSI) values of 2 or higher, and San Juan, Puerto Rico, saw 28 days at CSI 5, indicating a strong climate change influence on those specific days.

• The United States experienced cooler than average temperatures in August 2025, with an average anomaly of -0.5°F across 196 analyzed cities. The Northeast was the most unusually cold region, averaging -2.1°F, and Roanoke, Virginia, was the coldest city at -4.4°F below normal.
• Despite the cooler August 2025 average, 189 of the 196 analyzed cities have shown long-term warming trends for August since 1970. Reno, Nevada, recorded the most significant increase, with average August temperatures now 11.1°F warmer than in 1970.
• Climate change significantly influenced temperatures in specific locations during August 2025. Twenty-seven cities had at least two weeks of Climate Shift Index (CSI) values of 2 or higher, with the Southwest region averaging the highest number of such days (20). San Juan, Puerto Rico, experienced 28 days at CSI 5, meaning temperatures on those days were at least five times more likely due to climate change.
• Eugene, Oregon, was the most unusually hot city in August 2025, recording a temperature 3.9°F warmer than usual.

APA

Climate Central (2025). Monthly Attribution Overview – August 2025. https://www.climatecentral.org/report/monthly-attribution-overview-august-2025

Chicago

Climate Central. Monthly Attribution Overview – August 2025. 2025. https://www.climatecentral.org/report/monthly-attribution-overview-august-2025.

Wikipedia

{{cite report |author=Climate Central |title=Monthly Attribution Overview – August 2025 |date=3 September 2025 |url=https://www.climatecentral.org/report/monthly-attribution-overview-august-2025 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2025monthly, author = {{Climate Central}}, title = {{Monthly Attribution Overview – August 2025}}, institution = {Climate Central}, year = {2025}, month = sep, url = {https://www.climatecentral.org/report/monthly-attribution-overview-august-2025}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }