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
| 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.
Rain
| 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.
Sun
| 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.
Humidity
| 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 Time | 2 am | 5 am | 8 am | 11 am | 2 pm | 5 pm | 8 pm | 11 pm |
| Humidity % | 45 | 51 | 46 | 33 | 25 | 23 | 29 | 38 |
Wind
| 6.6 mph | August wind speed average | 10.6 kph |
August is a little windier than most other months in Phoenix.
Storms
| 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.
Reference
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.