Monthly Attribution Overview - April 2025

In April 2025, 182 out of 191 analyzed U.S. cities were warmer than normal, with an average temperature anomaly of 2.1°F. The Southeast region experienced the most significant anomalies and the highest number of days with a Climate Shift Index (CSI) of 2 or above, indicating temperatures at least twice as likely to occur due to climate change. Shreveport, Louisiana, recorded the highest anomaly at 6.33°F, while Reno, Nevada, showed the fastest long-term April warming since 1970, increasing by 8.0°F.

• The vast majority of analyzed U.S. cities experienced above-normal temperatures in April 2025, with 182 of 191 cities being warmer than normal and an average temperature anomaly of 2.1°F. For 46 cities (24% of stations), this period ranked among the top 10 warmest April monthly temperatures on record.
• The Southeast region was particularly affected, containing all eight cities with temperature anomalies of 5°F or higher. Shreveport, Louisiana, had the highest anomaly at 6.33°F, marking its hottest April on record. In North Carolina, Raleigh, Charlotte, and Asheville also recorded their hottest April on record.
• Climate change significantly influenced temperature patterns, as evidenced by the Climate Shift Index (CSI). The Southeast had the highest average number of days (6.2) with a CSI of 2 or above, meaning those temperatures were at least twice as likely to occur because of climate change. Twenty-five cities nationwide experienced at least one week of days at or above a CSI of 2.
• Long-term data indicates widespread April warming since 1970, with 178 of 191 analyzed ACIS stations showing positive temperature trends. Reno, Nevada, experienced the most significant long-term increase, with average April temperatures 8.0°F warmer than in 1970.
• The report distinguishes between recent temperature anomalies and pre-industrial shifts using the CSI. For example, San Juan had a negative temperature anomaly relative to the 1991–2020 average but still had a high number of days with a CSI of 2 or higher, indicating it was significantly warmer than a pre-industrial April.

APA

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

Chicago

Climate Central. Monthly Attribution Overview - April 2025. 2025. https://www.climatecentral.org/report/monthly-attribution-overview-april-2025.

Wikipedia

{{cite report |author=Climate Central |title=Monthly Attribution Overview - April 2025 |date=5 May 2025 |url=https://www.climatecentral.org/report/monthly-attribution-overview-april-2025 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

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