Phoenix Will see 5 days of over 100 degree weather This Week
In March, Phoenix’s average daily low is 52°F and the average high is 77°F, with rain on only about three days during the month.
This week, however, Phoenix will see temperatures exceed 100°F for five consecutive days, from the 18th through the 22nd, peaking at 108°F on the 21st. Nighttime lows will not drop below 70°F any night this week, according to Accuweather. The National Weather Service has issued an “extreme heat watch” for Phoenix and the surrounding region, advising: “Take extra precautions if you work or spend time outside. When possible, reschedule strenuous activities to early morning or evening.”
According to Climate Analytics, the current heat event is being intensified by climate change — and conditions are expected to worsen significantly. The organization projects that by 2100, Phoenix will experience 1,297 hours per year that are considered unsafe for outdoor work. Tourism would be severely impacted, as would the construction industry, which would face major disruptions for much of the year.
Dr. Carl Schleussner, Science Advisor at Climate Analytics, warned: “The data is telling us that unless we do more to reduce our emissions, extreme heat will decimate working conditions outdoors.”
The heat also carries substantial financial costs — from emergency shelters to replacement tires for city vehicles. As the Federal Reserve Bank of San Francisco notes, data from FEMA’s National Risk Index shows that Arizona’s statewide expected annual losses from heat waves total approximately $6 million, with two-thirds of those losses attributed to death and injury.
Phoenix faces a second, compounding climate threat: it is getting drier. The city sits within a region gripped by a 1,200-year megadrought affecting the Southwest and parts of Mexico. As NPR has reported, the last comparable — though less severe — multidecade megadrought occurred in the 1500s. Even during summer, Phoenix averages only about half an inch of rain per month.
If global temperatures continue to rise unchecked, the consequences will grow increasingly deadly. In 2024, heat-related deaths in Maricopa County, which includes Phoenix, exceeded 600. Those most at risk include people without shelter, outdoor workers, and residents without air conditioning. Recent research also found that a multi-day power outage in Phoenix could increase severe heat-related health emergencies by 50%.
The number of days per year with high temperatures at or above 100°F is already extraordinarily high, as measured at Phoenix Sky Harbor International Airport by the National Weather Service:
Days at or above 100°F:
- 2023: 133 days
- 2024: 143 days — a record-breaking year that included 113 consecutive days above 100°F
- 2025: 122 days
Days at or above 110°F:
- 2023: 55 days, including a historic 31-day consecutive streak in July
- 2024: 70 days — the highest number of 110°F+ days ever recorded in Phoenix history
- 2025: 37 days, including 12 days in July and 9 in June
Historically, Phoenix’s 100°F days were largely confined to May through September. That window is now expanding, and early 2026 is already offering a stark example of how the extreme heat season is stretching further into the year.
Among large American cities, Phoenix stands alone. It averages around 125 days per year above 100°F — nearly double that of Las Vegas, the second-highest city, which averages 78 such days.
Sources: PBS, KIZZ, Axios, Weather-dot-gov, ABC News, Extreme Weather Watch, NPR, Weather.com, and NOAA.
