Phoenix Weather in August

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

This page gives detailed information on the typical August temperature, precipitation, sun, humidity, wind and storms for Phoenix.

The temperature and rainfall numbers here are historical averages based on climate data gathered in downtown Phoenix. The rest of the weather measurements are averages at the Phoenix Sky Harbor International Airport, located a few miles southeast of the city center.

Temperature Weather iconTemperature

104 °F August average high 40 °C
82 °F August average low 28 °C

In most years, Phoenix averages a daily maximum temperature for August that's between 103 and 106 degrees Fahrenheit (39 to 41 degrees Celsius). The minimum temperature usually falls between 80 and 84 °F (27 to 29 °C).

The days at Phoenix maintain steady temperatures during August, with no substantial cooling by the end of the month.

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 °F (21 °C) just once a decade on average.

Rainy Weather iconRain

1.0 in total precipitation 25 mm
3 days of rain

Half the time, Phoenix receives 0.3 to 1.2 inches (7 to 30 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.


These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals.

Phoenix Weather
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