4 Quick Facts About the Phoenix Heat

Phoenix heat during the summer months can be nearly intolerable. The temperatures rise well over 100 degrees for several months on end. Here are 4 facts about Phoenix heat to get you warmed up.

1) Phoenix is the hottest city in Arizona!

Some people are surprised to discover that not all of Arizona is as sweltering as Phoenix can be. Climates across the state can vary greatly! For example, the temperature in Flagstaff, which you’ll find in northern Arizona, has never actually reached 100 degrees! Highs in the summer climb well into the upper ninety’s, but the hundred-degree mark remains historically out of reach. Not only is Phoenix the hottest city in Arizona, but it also has the highest average summer highs of any major city in the United States. Phoenix also beats out every other city in the United States for having the most days where the temperature tops 100 degrees!

2) The Highest Temperature Recorded in Arizona was 122 Degrees!

This temperature was recorded back in June of 1990. To put it into perspective, the hottest temperature ever recorded on earth was a scorching 134 degrees in Death Valley, California. So, I think we can all agree that the Phoenix heat is no joke! The National Weather Service cites that, between 1896-2010, there were an average of ninety-two days that were 100 degrees or higher and an average of eleven days where the temperature topped 110 degrees. Some years are more punishing than others… For example, in 1911, zero-days were recorded where the temperature reached 110 degrees, but in 1989, 143 days were at least 100 degrees!

3) Summer Temperatures Go Beyond the Summer Months

The hottest temperatures tend to come at the peak of the summer, but in this city, toasty temps turn up during plenty of other times of the year too. The National Weather Service records show that the earliest Phoenix has ever gotten its first 100-degree day of the year was on March 26th! One year, it was 110 degrees by May 10th! As much as the sweltering temperatures like to come early, they also like to stay late. One year, on October 23rd, it was still 100 degrees! Records prove that it’s been as hot as 110 degrees as late as September 19th, too. If you’re lucky, there will be one day per year where Phoenix’s temperature drops to freezing or below. But, a record five-year span was once recorded where Phoenix didn’t even see any days with frost, so don’t expect a cool down anytime soon!

4) Phoenix is an Urban Heat Island (UHI)

Temperatures in Phoenix can be even hotter than the temperatures in surrounding areas because of the Urban Heat Island effect. Basically, the components of the city — its buildings, asphalt, concrete, etc — hold in the heat of the day. As the sun sets and temperatures in surrounding areas fall, high temperatures in the heart of the city are maintained. As a general rule, temperatures measured in the city are about ten degrees higher than temperatures measured in outlying areas.

An article by the Arizona Indicators cites a span of seven days in 2010 when the low temperatures recorded at Phoenix Sky Harbor Airport were over ninety degrees, and also, notably ten degrees higher than temperatures recorded in the southeast valley. While ten degrees might not seem like a big difference, when you’re talking about temperatures of 100 or 110 degrees, it can make a big difference. The same article voices concerns that the Urban Heat Island effect might ultimately “jeopardize the sustainability” of the city.