An extreme heat warning for metro Phoenix is set to go into effect at 11 a.m. March 19, as triple-digit temperatures continue to break records across the region.<\/p>\n
“We’re forecasting a high of 104 for March 19, which would break the current record of 96 degrees set in 2017,” said meteorologist Katherine Berislavich, of the National Weather Service.<\/p>\n
The extreme heat warning follows directly on the heels of record-breaking temperatures earlier this week, with Wednesday’s high of 102 marking the first triple-digit temperature this year, a new record high temperature for March and marking the earliest 100-degrees on record for Phoenix, according to Berislavich.<\/p>\n
The heat warning will be in effect until 8 p.m. on March 22.<\/p>\n
Berislavich encouraged Arizonans to take precautions similar to those taken in the summer months.<\/p>\n
Record-breaking March heat wave roasts Phoenix area. Take a look<\/p>\n
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A runner makes his way along Tempe Town Lake in Tempe, Ariz. on March 18, 2026. Temperatures were expected to reach triple digits, the earliest in the year in Arizona history.<\/p>\n
“Make sure you’re drinking plenty of water and electrolytes. If you are planning outdoor activities, try to do those early in the morning or later in the day and avoid the peak heat hours in the late morning and early afternoon. If you are outside, try to take breaks in the shade or inside.”<\/p>\n
One important thing to note about a heat wave this early is not to be deceived by the lower morning temperatures, said Berislavich.<\/p>\n
“Don’t be fooled by the cooler mornings,” she said. “During the summer, our overnight low is still usually in the upper 80s, low 90s. This time of year, we’re still seeing lows dip into the upper 60s. So when people are getting up, it’s still relatively cool out, but the temperature will rapidly increase throughout the morning.”<\/p>\n
Even before the extreme heat warning takes effect, soaring temperatures earlier this week have already prompted emergency responses on hiking trails across the Valley<\/a>. Starting on March 18 and running through March 22, the city will restrict access to several popular trails from 8 a.m. to 5 p.m., including Camelback Mountain and Piestewa Peak Summit Trail.<\/p>\n Valleywise Health physicians are warning that the early heat spike poses particular dangers because bodies \u2014 especially those of out-of-town visitors \u2014 haven’t had time to adjust to the high temperatures. Dr. Paul Pugsley, an emergency medicine physician at Valleywise Health Medical Center, said visitors may not recognize the early signs of heat illness, mistaking symptoms for simple fatigue or lightheadedness and pushing through when they shouldn’t.<\/p>\n See how Phoenix endured St. Patrick’s Day as unprecedented heat hit<\/p>\n 1 of 18<\/p>\n Hundreds gather to celebrate St. Patrick\u2019s Day at Tim Finnegan’s Irish Restaurant and Pub in Glendale on March 17, 2026.<\/p>\n