Excessive Heat Warning Issued as 100-Degree Temperatures, Record March Highs Forecast This Week

A historic heat wave is bearing down on Arizona this week, with temperatures expected to shatter all-time March records across the region.

According to the National Weather Service in Phoenix, a powerful ridge of high pressure is building over the Southwest and will drive temperatures into the 90s by Thursday before pushing into triple digits early next week. A forecast high of 101 degrees on Tuesday would mark the earliest triple-digit day ever recorded in Phoenix, breaking the previous record of March 26, 1988. Daily records are expected to fall every day from Tuesday through Friday.

Weather in Phoenix This Week

The warmup is happening fast. Today's high in the Phoenix area was around 84 degrees — already seven degrees above normal for this time of year. Temperatures climb into the low to mid 90s Thursday through Monday before the heat intensifies further into the following week.

The National Weather Service notes that not only are all-time March temperature records likely to be broken, but the earliest-ever occurrence of 100 degrees in Phoenix is also on the line. The agency has already issued a First Alert Weather Day for next Tuesday, with additional First Alert days expected as the ridge strengthens.

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City of Phoenix officials are expanding heat response measures in anticipation, keeping a 24/7 respite center open at 20 W. Jackson Street and extending hours at cooling locations across the metro area. Residents are urged to limit outdoor activities during the hottest parts of the day, stay hydrated, and check on elderly neighbors and other vulnerable individuals.

The NWS may issue additional heat watches or advisories as the forecast develops.