Arizona, California Severe Extreme Heat Warning | Effective 07/21/2026 11:58

Headline: 
Extreme Heat Warning issued July 21 at 11:58AM MST until July 27 at 8:00PM MST by NWS Phoenix AZ
Event: 
Extreme Heat Warning
Urgency: 
Expected
Effective: 
July 21, 2026 - 11:58am
Expires: 
July 22, 2026 - 5:00am
Description: 
* WHAT...Dangerously hot conditions possible. Afternoon temperatures 108 to 116. Major Heat Risk. * WHERE...In Arizona, Central La Paz, Gila River Valley, Kofa, and Southeast Yuma County. In California, Joshua Tree National Park. * WHEN...From 10 AM MST /10 AM PDT/ Thursday to 8 PM MST /8 PM PDT/ Monday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events. Overexposure can cause heat cramps and heat exhaustion to develop and, without intervention, can lead to heat stroke.
Instruction: 
An Extreme Heat Warning means that a period of very hot temperatures, even by local standards, will occur. Actions should be taken to lessen the impact of the extreme heat. Take extra precautions if you work or spend time outside. When possible, reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose-fitting clothing when possible and drink plenty of water. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1. Public cooling shelters are available in some areas. Consult county officials for more details.
Area Description: 
Kofa; Central La Paz; Southeast Yuma County; Gila River Valley; Joshua Tree NP West; Joshua Tree NP East
Forcast Office: 
NWS Phoenix AZ