Phoenix is Breaking Daily Heat Records Again – And It’s Only April

This Summer Is Going to be a Scorcher

As April 2025 kicks off, Phoenix is already roasting with temperatures way above normal. This could be a sign of yet another record-breaking summer in America’s hottest major city. But first, have you ever wondered who actually decides what the “official” temperature is?

Official Temp Readings Come from the Airport

The National Weather Service (NWS) uses readings from Phoenix Sky Harbor International Airport for all official temperature records in the city. It’s been the official data source since 1953.

There are other weather stations around Phoenix, such as the Salt River Project and the FAA, but Sky Harbor Airport is the only official one by the NWS. Speaking of the airport…

Phoenix Once Got So Hot Airplanes Couldn’t Take Off

Phoenix set its all-time heat record on June 26, 1990, when temps at Sky Harbor Airport hit 122°F (50°C). This record has stood for over 30 years and remains the hottest temperature ever recorded in the city.

The heat was so bad that Sky Harbor Airport had to close for several hours. Officials worried planes couldn’t get enough lift to safely take off in such extreme conditions.

2024 Was a Scorcher

2024 broke records as Phoenix’s hottest year with an average temperature of 78.6°F, beating the previous record by 1.3 degrees. The city reached 110°F or hotter on 70 different days in 2024.

Even more impressive, Phoenix had 113 straight days with temperatures over 100°F, smashing the old record of 76 days set back in 1993.

Phoenix Suffered a Heat Streak in 2023

Summer 2023 brought Phoenix’s most intense heat wave on record. The city suffered through 31 consecutive days of 110°F or higher temps in July, destroying the previous record of 18 days from 1974.

July 2023 made Phoenix the first major U.S. city to average over 100°F for a whole month, with an average temp of 102.74°F. Making matters worse, 2023 also had the driest monsoon season on record, so there was no natural relief from the heat.

Heat Deaths Have Are at An All-Time High

Heat killed 645 people in Maricopa County in 2023, a 50% jump over the previous record of 425 heat-related deaths in 2022. This marked the 7th straight year of record heat deaths in the county.

This represents a 700% increase in heat-related deaths compared to ten years earlier. About three-quarters of those who died were male, and 78% of deaths happened outdoors.

January 2025 Was Hot Enough To Break Records From 1989

Phoenix started breaking records early in 2025, with a new daily high of 81°F on January 3, beating the old record of 79°F from the same day in 1989. By February 4, Phoenix broke a 100-year-old record with a high of 86°F.

Then in late March, the city nearly hit 100°F, reaching 99°F on March 25. Had it reached triple digits, it would have been the earliest 100-degree day ever recorded in the city.

100°F Days Are Now Coming Earlier

Based on historical averages, Phoenix typically hits its first 100°F day around May 11. Looking at just the last 30 years, though, the first triple-digit day now happens around May 2, showing a trend toward earlier extreme heat.

In 2024, Phoenix reached 100°F on April 21, and before that, the city had only hit 100°F in March once (back in 1988).

Phoenix Now Has 8x More Blazing Hot Days Than In 1900

In the early 1900s, Phoenix averaged only five days per year with temperatures at or above 110°F. This grew to seven days annually by the 1950s and 27 days by the 2010s.

Since 2021, the city now averages 42 days per year at or above 110°F. That’s eight times more scorching days than a century ago, when Phoenix averaged about five such days per year.

Phoenix Has Too Few Trees To Keep The City Cool

Phoenix currently has an average tree coverage of only 9-11%, far below the city’s goal of 25% tree canopy by 2030 as outlined in the Tree and Shade Master Plan.

Studies show that each 1% increase in tree canopy can reduce air temperatures by about 0.14°C (0.25°F). If Phoenix reaches its 25% goal, temperatures could drop by up to 2.0°C (3.6°F) in residential areas.

Phoenix Stays 15° Hotter At Night vs. Rural Areas

Thanks to the urban heat island effect, Phoenix’s nighttime low temperatures stay 10 to 15 degrees warmer than surrounding rural areas. This prevents the city from cooling off at night.

During the day, asphalt can heat up to 180 degrees, then release that heat after sunset. This combo of urban heat island effect with global warming has made Phoenix’s heat problems worse, taking away the cooling that usually happens at night.

Some Phoenix Neighborhoods Have it Worse

Some Phoenix neighborhoods can be as much as 13° hotter than others on the same day. The hottest areas typically have fewer trees and more pavement.

Research on Southwestern cities shows that the poorest 10% of neighborhoods are on average 2.2°C (4°F) hotter than the wealthiest 10%. This happens on both extreme heat days and average summer days.

Fingers Crossed for More Trees & "Cool Corridors"

Phoenix wants to increase tree coverage from the current 9-11% to 25% by 2030 through its Tree and Shade Master Plan. The city’s Office of Heat Response and Mitigation is working to create 100 cool corridors by 2030.

These will focus on areas with lots of pedestrians to make walking more bearable during extreme heat. When completed, you’ll find these paths with more trees, shade structures, and cool pavements. The goal is to make it possible to move around the city even on the hottest days.

Brace for Hotter Days Ahead

The number of days above 110°F in Phoenix is expected to more than double by 2060. This makes heat management crucial since 60% of Arizona’s population lives in the Phoenix area.

This forecast is driving investments in heat-resistant infrastructure and cooling technologies throughout the metro area. Without these changes, life in future Phoenix summers would become increasingly dangerous.