Phoenix Weather in August

August continues the extreme heat of summer at Phoenix, Arizona. The weather is also slightly more humid now than the earlier in the season.

This page gives detailed information on the typical August temperature, precipitation, sun, humidity, wind and storms for Phoenix. The weather measurements are averages based on climate data gathered at Phoenix Sky Harbor International Airport, located near the city center.

Temperature Weather iconTemperature

105 °F August average high 41 °C
84 °F August average low 29 °C
27 days 100 °F max. or more (38 °C)
0 days 70 °F min. or less (21 °C)

During August, the temperature in Phoenix dips to 70 degrees Fahrenheit (21 degrees Celsius) just once a decade on average.

Rainy Weather iconRain

0.9 in total precipitation 24 mm
5 days of rain

Half the time, Phoenix receives 0.4 to 1.3 inches (10 to 33 mm) of rainfall in August. One in four years has drier weather, while another one in four is wetter.

Sunny Weather iconSun

85 % sunshine
18 days clear skies

The sun's rays reach the ground in Phoenix during 85 percent of daylight hours on average in August, for a total of 352 hours in the month. Typically on 18 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in August at Phoenix lasts for 13 hours and 20 minutes a day on average. The longest day of the month is the 1st with 13 hours and 47 minutes of daylight. By the end of the month, the days have shortened to 12:53 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

36 % August average humidity

The relative humidity in Phoenix during August usually peaks at 51 percent in the morning then drops to 23 percent by late afternoon.

Local Time2 am5 am8 am11 am2 pm5 pm8 pm11 pm
Humidity % 45 51 46 33 25 23 29 38

Windy Weather iconWind

6.6 mph August wind speed average 10.6 kph

August is a little windier than most other months in Phoenix.

Stormy Weather iconStorms

1 day rainfall of 0.5 inches (13 mm) or more
7 days with thunderstorms in August

Every few years, Phoenix receives an inch (25 mm) or more of rain in one day during August.

Thunderstorms at Phoenix are most common during August.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.

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