Monthly Attribution Overview – May 2026

In May 2026, the United States experienced slightly below-average temperatures overall, with an average anomaly of -0.2°F across 192 cities. Despite this, the western U.S. saw above-average temperatures, and the Northern Rockies and Plains region was the warmest, averaging more than 1.6°F above normal. Long-term data indicates that 185 of the 192 analyzed cities have warmed since 1970, with Reno, Nevada, showing the greatest increase at 7.5°F. Climate attribution analysis shows that San Juan, Puerto Rico, had the highest number of days (28) where temperatures were at least two times more likely due to climate change (CSI level 2 or higher).

• The United States had an average temperature anomaly of -0.2°F across 192 cities in May 2026, with 105 cities recording colder-than-average conditions and 83 recording warmer-than-average conditions.
• Regional temperature variations were evident, with the Northern Rockies and Plains being the warmest region, exceeding normal temperatures by more than 1.6°F. West Palm Beach, Florida, was the most unusually warm city, recording a temperature 4.1°F above usual.
• Long-term warming trends since 1970 are present in 185 of the 192 analyzed cities. Reno, Nevada, experienced the most significant increase, with average May temperatures rising by 7.5°F since 1970.
• Climate attribution analysis using the Climate Shift Index (CSI) indicates that San Juan, Puerto Rico, had 28 days in May 2026 where temperatures were at least two times more likely because of climate change. On average, cities in the Southeast region had the highest number of such days, averaging 7.

APA

Climate Central (2026). Monthly Attribution Overview – May 2026. https://www.climatecentral.org/report/monthly-attribution-overview-may-2026

Chicago

Climate Central. Monthly Attribution Overview – May 2026. 2026. https://www.climatecentral.org/report/monthly-attribution-overview-may-2026.

Wikipedia

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

BibTeX

@techreport{climatecentral2026monthly, author = {{Climate Central}}, title = {{Monthly Attribution Overview – May 2026}}, institution = {Climate Central}, year = {2026}, month = may, url = {https://www.climatecentral.org/report/monthly-attribution-overview-may-2026}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }