Hottest June in Phoenix

By Erinanne Saffell, posted 7/1/2024

For Arizona, June 2024 was much warmer, with Phoenix, Flagstaff, Winslow, and Prescott setting records. Let’s zoom into some Phoenix June records.

Climatological statistics often evaluate “average” numbers. Here’s how some are calculated:

• The average monthly temperature is calculated as the average monthly maximum temperature plus the average monthly minimum temperature divided by two (max+min/2).

• The average monthly maximum temperature adds all the maximum temperatures for the month, then divides by the days in the month. The same calculation is used for the average monthly minimum temperature.

Here are the June stats for Phoenix:

June 2024 was the hottest June on record (to date), with an average monthly temperature of 97.0°F.

• 2024 average June maximum: 109.4° (record)
• Previous record: 108.6° (1974)
• Change in temperature: + 0.8°F

• 2024 average June minimum: 84.6° (record)
• Previous record: 82.5°F (2021)
• Change in temperature: + 2.1°F

The average minimum temperature change was nearly 3 times greater than the average maximum temperature change. Minimum temperatures are largely impacted by urbanization, as parking lots and sidewalks hold heat during the day and release it slowly at night (more information here).

Phoenix had 14 days of 110°F or higher this June 2024. In the early 1900s, the average was 5 days a year with 110°F or higher (1901-1910). In 2011-2020, the average was 27 days a year, more than 5 times greater (this statistic includes the 53 days in 2020).

Phoenix June records of 110°F or higher:

• June 2024: 14 days
• Long-term average of 110°F or higher: 4 days (1896-2024)
• Last 10-year average: 8.5 days (2015-2024)
• Record: 18 days in 1974
• Last previous highest number: 2008 with 14 days

Interestingly, the first month that can reach 110°F or higher in Phoenix is May, with 13 different years in Phoenix reaching 110°F or higher (first May with 110°F or higher? 1896; latest May with 110°F or higher? 2020).