Phoenix woke up Saturday to clear skies and mid-60s readings, but the comfortable morning is just the opening act for a major early-season heat surge. Forecasters say today will climb into the low 90s, and a stubborn pattern could push the Valley into the triple digits later this week.
What the NWS Is Warning
The National Weather Service has issued an Extreme Heat Watch for parts of southern Arizona as an unusually strong ridge builds over the Desert Southwest. Forecasters note Phoenix could reach 100°F as early as Wednesday, March 18, 2026, with highs topping 105°F by Thursday or Friday, values that would break daily and monthly March records. According to NWS Phoenix, consecutive record highs are possible late next week if the pattern holds.
How Hot And When
Expect a rapid jump: Saturday’s high should top out near 92°F, with low-90s lingering through Monday. Temperatures climb sharply after that, with forecasts showing Tuesday near 97°F, Wednesday around 100–101°F, and widespread readings in the mid-100s (about 104–106°F) by Thursday and Friday.
Where To Find Relief
The City of Phoenix has rolled out a 2026 Heat Response Plan that lists a 24/7 respite center at 20 W. Jackson St. and a partner site at Justa Center, 1001 W. Jefferson St., to help people without reliable air conditioning. The plan formalizes expanded cooling hours and outreach, though full program rollouts are typically scheduled for May, so check hours before you go. For program details and locations, see the City of Phoenix heat response page.
Heat Safety
Take precautions now: shift strenuous work and exercise to early morning or evening, carry water, and wear light, loose clothing. Never leave children or pets in parked cars and check on older neighbors or anyone who may lack air conditioning. If you work outdoors, schedule frequent breaks in shaded or cool spaces and watch for signs of heat exhaustion or heat stroke.
Bottom Line
This is an unusually early and potentially record-setting heat event for Phoenix, with an Extreme Heat Watch covering late next week and triple digits likely if forecasts verify. For background on how fast this pattern came together, see our earlier report on the looming March heat blast.
