Phoenix Weather in December
December has the coolest and cloudiest weather of the year for Phoenix. In this southern Arizona city that means pleasantly mild temperatures and mostly sunny skies.
This page gives detailed information on the typical December 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.
|66 °F||December average high||19 °C|
|45 °F||December average low||7 °C|
December is the coldest month overall for Phoenix and the 20th to 27th are its chilliest days. They have daily highs averaging 65 degrees Fahrenheit (18 degrees Celsius) and lows of 44 °F (7 °C).
|11 days||70 °F max. or more (21 °C)|
|26 days||50 °F min. or less (10 °C)|
Nearly every December day warms to over 60 °F (16 °C) in Phoenix. Temperatures in December above 80 °F (27 °C) happen once every few years.
The thermometer dips to 40 °F (4 °C) or below on 7 nights. December averages just one night a decade when the temperature drops to freezing.
|0.7 in||total precipitation||19 mm|
|4 days||of rain|
Half the time, Phoenix receives 0.2 to 1.0 inches (5 to 25 mm) of rainfall in December. One in four years has drier weather, while another one in four is wetter.
|15 days||clear skies|
December is the cloudiest month for Phoenix. The sun's rays reach the ground during 77 percent of daylight hours on average, for a total of 238 hours in the month. Typically on 15 days this month the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in December at Phoenix averages 9 hours and 58 minutes a day. The shortest days of the year, from around December 17th to 24th, last 9 hours and 56 minutes from sunrise to sunset.
|52 %||December average humidity|
The relative humidity in Phoenix during December usually peaks at 67 percent in the morning then drops to 33 percent by late afternoon. December is the most humid month for Phoenix.
|Local Time||2 am||5 am||8 am||11 am||2 pm||5 pm||8 pm||11 pm|
|5.1 mph||December wind speed average||8.2 kph|
The wind at Phoenix is calmest overall during December.
|0 days||rainfall of 0.5 inches (13 mm) or more|
|1 day||with thunderstorms in December|
December is the month that Phoenix is most likely to receive an inch (25 mm) or more of rain in one day. Most years, though, Phoenix doesn't see rain that heavy in December.
Phoenix averages one December thunderstorm every two years.
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.