Cities with most 100-degree days? Where Phoenix ranks in U.S.

Looking at the weather app each morning during a Valley summer might feel a bit comical. Nearly every day forecasts the same outlook: hot.

From 1991 to 2020, Phoenix residents experienced triple-digit temperatures an average of 111 days each summer, according to the National Weather Service. This year, Phoenix has already had 90 days of at least 100-degree weather. In 2020, the city hit a record with 145 days of triple-digit temperatures, which accounts for nearly 40% of the entire year.

But what does this look like in the long term? Phoenix has had thousands of triple-digit days. Since the early 1900s, the Valley of the Sun has had 11,410 days where the temperature hit at least 100 degrees, blowing any other major U.S. city out of the water, according to AccuWeather. That's the equivalent of more than 31 years.

How many times have cities across America reached 100º in recorded history? Some of them might surprise you! https://t.co/ymTj8nAPnC pic.twitter.com/u3kcHuCj78

— AccuWeather (@accuweather) August 17, 2025

Located in the Sonoran Desert, Phoenix is a literal hotbed for record-breaking heat. Air comes from the south and retains heat. Normally, Phoenix’s monsoon season helps temperatures cool off slightly in the summer, only to shoot back up again. But this summer, monsoon activity has been sparse.

However, as every Phoenix resident knows, the scale doesn’t stop at 100 degrees. In fact, a 101- or 102-degree day is often a welcome respite in the summer. Over the last three decades, Phoenix has averaged 21 days each summer with temperatures reaching at least 110 degrees, according to the NWS. This summer has already flown past that average with 33 days of 110-degree days. Last year, Phoenix had a record-breaking 70 days of 110-plus-degree heat.

High temperatures this afternoon were within 1-2 degrees of daily records at all three of our primary climate sites. This will be common for the next few days as well, as the heat continues. #azwx #cawx pic.twitter.com/KhfqrLknuJ

— NWS Phoenix (@NWSPhoenix) August 21, 2025

Phoenix has had more than 1,800 days of 110-plus-degree temperatures since the early 20th century, per AccuWeather.

How do Phoenix’s 11,410 days of 100-degree weather compare to other major U.S. cities — specifically, those with at least 500,000 residents — as tracked by AccuWeather? Here’s the top five.

1. Phoenix – 11,410
2. Las Vegas – 8,750 days
3. Dallas – 2,270 days
4. Austin – 1,680
5. Oklahoma City – 1,580 days