Phoenix Weather in September
September begins a steady deline in temperature for Phoenix, Arizona. At the same time, rain and thunderstorms become less common.
This page gives detailed information on the typical September 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.
|100 °F||September average high||38 °C|
|75 °F||September average low||24 °C|
In most years, Phoenix averages a daily maximum temperature for September that's between 98 and 102 degrees Fahrenheit (37 to 39 degrees Celsius). The minimum temperature usually falls between 74 and 77 °F (23 to 25 °C).
The days at Phoenix begin to cool down quickly during September. By the end of the month, the temperature has dropped around 8 °F (5 °C) below what it was at the start.
|17 days||100 °F max. or more (38 °C)|
|5 days||70 °F min. or less (21 °C)|
Nearly every day in September heats up to over 90 °F (32 °C) in Phoenix. At night, the temperature never dips below 60 °F (16 °C) in September.
|0.6 in||total precipitation||15 mm|
|3 days||of rain|
Half the time, Phoenix receives 0.1 to 0.9 inches (3 to 23 mm) of rainfall in September. One in four years has drier weather, while another one in four is wetter.
|22 days||clear skies|
The sun's rays reach the ground in Phoenix during 89 percent of daylight hours on average in September, for a total of 330 hours in the month. Typically on 22 days this month the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in September at Phoenix lasts for 12 hours and 21 minutes a day on average. The longest day of the month is the 1st with 12 hours and 51 minutes of daylight. By the end of the month, the days have shortened to 11:51 from sunrise to sunset. These durations can vary by a minute or two from year to year.
|36 %||September average humidity|
The relative humidity in Phoenix during September usually peaks at 50 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|
|6.3 mph||September wind speed average||10.1 kph|
September is an average month in Phoenix for wind speed.
|1 day||rainfall of 0.5 inches (13 mm) or more|
|4 days||with thunderstorms in September|
About once a decade, Phoenix receives an inch (25 mm) or more of rain in one day during September.
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.