An Extreme Heat Warning is in effect right now across a wide stretch of Southern California, covering areas including the Coachella Valley, Indian Wells Valley, San Diego County Inland Valleys and Mountains, Riverside County Mountains, Orange County Inland, the San Bernardino and Riverside County Valleys (the Inland Empire), the Santa Ana Mountains and Foothills, Apple and Lucerne Valleys, the Western Antelope Valley Foothills, the Cuyama Valley, and the Interstate 5 Corridor. The warning was issued July 31, 2026, at 1:35 PM PDT and remains in effect through August 3, 2026, at 11:00 PM PDT. It was issued jointly by the National Weather Service offices in Hanford CA, San Diego CA, and Los Angeles/Oxnard CA.
This is not a watch or advisory. An Extreme Heat Warning represents the highest level of heat alert the National Weather Service issues, reserved for conditions that pose a direct threat to human life, particularly for those without reliable access to cooling.
What the National Weather Service Is Telling You to Do Right Now
The National Weather Service is direct in its guidance: drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check on relatives and neighbors. These are not general suggestions. During an Extreme Heat Warning, they are the actions most likely to prevent a medical emergency.
One of the most critical warnings in the alert concerns vehicles. Do not leave young children or pets in unattended cars. Car interiors can reach lethal temperatures within minutes, even with windows cracked. This applies at any hour of the day during a warning of this magnitude.
If you need to be outside, NWS instructs residents to wear lightweight, loose-fitting clothing and to limit strenuous physical activity to early morning or evening hours, when temperatures are lower. If you or someone nearby begins showing signs of heat exhaustion or heat stroke, including heavy sweating, confusion, rapid pulse, or loss of consciousness, take action immediately. Heat stroke is a medical emergency requiring a 911 call.
For residents without air conditioning at home, the National Weather Service specifically advises seeking out cooling resources provided by local community management. Many cities and counties across the affected areas open cooling centers during Extreme Heat Warnings. Contact your local emergency management office or check your city or county website for the nearest location and hours. Do not wait until you feel unwell to find a cooler environment.
The NWS guidance closes with a clear three-part instruction: stay cool, stay hydrated, stay informed. Monitoring official sources throughout the duration of this warning, through August 3 at 11:00 PM PDT, is essential, as conditions can shift and additional guidance may be issued.
Why Preparedness Planning Matters Beyond This Warning
Extreme heat is the deadliest weather hazard in the United States on an annual basis, and it is one where household preparedness decisions made before a warning is issued make the largest difference. Knowing in advance which cooling centers are in your area, keeping emergency water supplies on hand, and having a plan for elderly or medically vulnerable family members are steps that cost little time but can prove critical when a warning like this one arrives. According to federal disaster declaration data, fire remains the most persistent and broadly declared disaster across the western United States, with 17 of the last 30 federal declarations in the past 60 days tied to fire events in states including Washington, Colorado, Utah, and Oregon. During periods of extreme heat, fire risk climbs alongside human health risk, making this a meaningful time to review your household preparedness posture across both hazards. The goal at USRiskRadar is to give you the practical, specific information that helps you act before conditions force the decision.
For the fundamentals that apply beyond this specific alert, see our Extreme Heat Preparedness guide.
Source: National Weather Service (NWS Hanford CA, NWS San Diego CA, NWS Los Angeles/Oxnard CA). Active alert data retrieved 2026-07-31 22:00 UTC via api.weather.gov.
