Monthly Attribution Overview – January 2026

In January 2026, the United States experienced an average temperature anomaly of -1.2°F, with 133 cities recording cooler-than-average conditions. Despite this national trend, the western U.S., particularly the Northern Rockies & Plains, saw significant warming, with Helena, Montana, recording the highest anomaly at 9.1°F. Long-term data indicates that 191 of the 194 analyzed cities have experienced warming trends since 1970, with Great Falls, Montana, showing the largest increase of 9.6°F. Climate attribution analysis using the Climate Shift Index (CSI) highlighted that San Juan, Puerto Rico, had 24 days where temperatures were at least five times more likely due to climate change.

• The United States generally experienced below-average temperatures in January 2026, with an average anomaly of -1.2°F across 194 analyzed cities. While 133 cities were cooler than average, 57 were warmer, and two were near-normal.
• Regional temperature variations were stark, with the Northern Rockies & Plains being the most unusually warm region (average anomalies exceeding 3.3°F) and the Ohio Valley being the most unusually cold (average anomalies of -3.9°F). Helena, Montana, was the warmest city relative to normal, at 9.1°F above average.
• Long-term trends show consistent warming since 1970 for nearly all analyzed locations (191 out of 194 cities). Great Falls, Montana, recorded the most significant increase, with average January temperatures rising 9.6°F since 1970.
• Climate attribution analysis using the Climate Shift Index (CSI) showed that San Juan, Puerto Rico, had 24 days in January 2026 where temperatures were at least five times more likely to occur because of climate change. On average, cities in the West had the highest number of days (12) with a CSI of 2 or above.

APA

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

Chicago

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

Wikipedia

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

BibTeX

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