Climate Shift Index Alert

A heat event in the Western U.S. from July 8-11, 2025, is forecast to bring temperatures 5-12°F above normal, with human-caused climate change making the event at least three to five times more likely for tens of millions of people.

• Between July 8-11, 2025, extreme heat in the Western U.S. will be at least three times more likely for approximately 43 million people and five times more likely for over 25 million people due to human-caused climate change.
• Forecasted temperatures for the period include 90-103°F (32-39°C) in Colorado, Utah, northwest New Mexico, and east Arizona, which is 8-12°F (4-7°C) above normal. Southwest Arizona and southern California deserts may see temperatures exceeding 110°F (43°C), more than 5°F (3°C) above normal.
• Cities including Phoenix, Santa Fe, Fresno, Las Vegas, and Denver will reach a Climate Shift Index (CSI) level of 5, meaning human-caused climate change made the event at least five times more likely.

APA

Climate Central (2025). Climate Shift Index Alert. https://www.climatecentral.org/climate-shift-index-alert/western-us-july-2025

Chicago

Climate Central. Climate Shift Index Alert. 2025. https://www.climatecentral.org/climate-shift-index-alert/western-us-july-2025.

Wikipedia

{{cite report |author=Climate Central |title=Climate Shift Index Alert |date=7 July 2025 |url=https://www.climatecentral.org/climate-shift-index-alert/western-us-july-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 = jul, url = {https://www.climatecentral.org/climate-shift-index-alert/western-us-july-2025}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }