As of 11:30 a.m. Arizona time Monday, Sept. 7: An Extreme Heat Warning is set to cover the Phoenix metropolitan area from 10 a.m. Tuesday through 8 p.m. Thursday, with afternoon temperatures of 105 to 109 degrees expected across the warned area.
The National Weather Service Phoenix warning includes Avondale, Goodyear, Peoria, Surprise, Sun City West, Wittmann and other communities in the Northwest Valley and Buckeye/Avondale forecast zones. The agency classifies the expected conditions as Major HeatRisk, a level at which heat-related illnesses increase significantly.
Separate portions of the warning cover the Tonopah Desert, Arlington, Wintersburg and other lower-desert areas of western Maricopa County during the same Tuesday-through-Thursday window. Forecast highs there are 104 to 109 degrees.
Heat is expected to peak midweek
The warning was current in an 8:39 a.m. Monday National Weather Service update. The Phoenix office said temperatures will run about 5 to 10 degrees above normal at the middle of the workweek before gradually easing over the weekend.
The alert is based on health risk as well as temperature. The Weather Service said prolonged exposure can lead from heat cramps and heat exhaustion to heat stroke. People working outdoors should move strenuous activity to the early morning or evening when possible and take frequent breaks in shade or air conditioning.
Heat stroke is a medical emergency. Confusion, loss of consciousness, very hot skin or other severe symptoms require an immediate call to 911. Children, older adults, outdoor workers, people without reliable air conditioning and people with certain medical conditions face elevated risk during sustained heat.
Where to find cooling help
Maricopa County residents can call 2-1-1 for free cooling-center information, transportation options, water and other heat-relief resources. 211 Arizona says live assistance is available from 9 a.m. to 7 p.m. daily in English and Spanish, with other languages available through interpreters. Service locations and hours can change, so residents should verify a site before traveling.
Peoria’s seasonal cooling centers and hydration stations remain scheduled to operate through Sept. 30. Surprise also lists indoor cooling and respite locations, including the Surprise Resource Center and city libraries, through the end of September. The county heat page at Maricopa.gov/heat provides current regional information.
For households with air conditioning, the Weather Service recommends using it during the hottest hours, drinking water regularly and checking on relatives or neighbors who may be vulnerable. Pets should not be left in parked vehicles and need shade and water when outside.
The warning is scheduled to expire at 8 p.m. Thursday, but weather alerts can be extended or changed. Residents should check the National Weather Service Phoenix office for the latest status.
Featured graphic: National Weather Service Phoenix, Sept. 7, 2026. The official warning graphic covers the broader forecast area; the Phoenix metro portion runs Tuesday through Thursday.