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 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

67 °F December average high 20 °C
45 °F December average low 7 °C

In most years, Phoenix averages a daily maximum temperature for December that's between 65 and 70 degrees Fahrenheit (18 to 21 degrees Celsius). The minimum temperature usually falls between 43 and 46 °F (6 to 8 °C).

December is the coldest month overall for Phoenix and the 19th to 22nd are its chilliest days. They have daily highs averaging 66.5 °F (19.2 °C) and lows of 44.4 °F (6.9 °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 about once a decade.

The thermometer dips to 40 °F (4 °C) or below on 6 nights. December averages just two nights a decade when the temperature drops to freezing.

Rainy Weather iconRain

0.9 in total precipitation 22 mm
3 days of rain

Every few years, Phoenix receives no rain in December. The rainiest Decembers get at least 1.2 inches (29 mm).

Sunny Weather iconSun

77 % sunshine
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.

Humid Weather iconHumidity

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 Time2 am5 am8 am11 am2 pm5 pm8 pm11 pm
Humidity % 63 66 67 46 34 33 48 57

Windy Weather iconWind

5.1 mph December wind speed average 8.2 kph

The wind at Phoenix is calmest overall during December.

Stormy Weather iconStorms

1 day 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.


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.

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