Extreme Heat Warning Issued for Imperial Valley and Desert Mountains

Overview

• The National Weather Service in Phoenix issued an Extreme Heat Warning that covers Imperial County and specific desert and mountain spots including the Chuckwalla Mountains, Chiriaco Summit and Joshua Tree National Park through Aug. 9.
• Afternoon highs are forecast around 110–118°F in the Imperial Valley and about 98–114°F in the named desert and mountain locations, with desert nights largely staying in the 80s to 100s and limited overnight cooling.
• Local forecasts say monsoon moisture will raise humidity countywide and create a slight chance of afternoon and evening storms in mountains and deserts later this weekend and into early next week.
• Officials are urging protective actions such as using cooling centers, staying hydrated, and following OSHA guidance to schedule frequent rest breaks for outdoor workers to reduce heat-illness risk.
• The persistent heat pattern follows a broader late‑July heat dome that has driven repeated NWS warnings, and the combination of hotter days, warmer nights and higher humidity raises the chance of increased heat-related illness, greater cooling demand and stress on power and emergency services.