Climate Shift Index Alert

A forecast for extreme heat across the Southwest U.S. and northern Mexico indicates temperatures up to 18°F above normal, with the Climate Shift Index (CSI) attributing a level 5 likelihood to human-caused climate change. Approximately 53 million people are expected to be affected by these conditions, which are compounded by persistent drought in the region.

• The Climate Shift Index (CSI) has reached level 5, the highest possible rating, indicating that human-caused climate change made the forecast extreme heat at least five times more likely.
• Nearly 53 million people are projected to experience at least one day of these exceptional, climate-driven conditions during the event period.
• Forecasted daytime highs from August 4 through 8 are expected to be 8°F to 13°F above average for much of the Southwest, southern Plains, and West, with some areas in northern Mexico and Nebraska seeing departures between 15°F to 18°F.
• Extreme temperatures are expected to reach between 110°F and 116°F in Sonora (Mexico), southern Nevada, southwest Arizona, and Southern California, with elevated nighttime lows between 87°F and 95°F in those same areas.
• The region is experiencing moderate to exceptional drought, which is drying the Rio Grande Valley and impacting hydropower, international trade agreements, and agriculture.

APA

Climate Central (2025). Climate Shift Index Alert. https://www.climatecentral.org/climate-shift-index-alert/SouthwestUS-Mexico-August-2025

Chicago

Climate Central. Climate Shift Index Alert. 2025. https://www.climatecentral.org/climate-shift-index-alert/SouthwestUS-Mexico-August-2025.

Wikipedia

{{cite report |author=Climate Central |title=Climate Shift Index Alert |date=5 August 2025 |url=https://www.climatecentral.org/climate-shift-index-alert/SouthwestUS-Mexico-August-2025 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2025climate, author = {{Climate Central}}, title = {{Climate Shift Index Alert}}, institution = {Climate Central}, year = {2025}, month = aug, url = {https://www.climatecentral.org/climate-shift-index-alert/SouthwestUS-Mexico-August-2025}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }