San Antonio Weather in December

San Antonio, Texas enjoys mild weather during December. Although there can be a few nights of frost, most days are balmy.

This page gives detailed information on the typical December weather for San Antonio.

You can jump directly to data and descriptions for:

The numbers here are historical averages based on climate data gathered at the San Antonio International Airport, located a few miles north of the city center.

Temperature Weather iconTemperature

64 °F December average high 18 °C
42 °F December average low 5 °C

In most years, San Antonio averages a daily maximum temperature for December that's between 60 and 68 degrees Fahrenheit (16 to 20 degrees Celsius). The minimum temperature usually falls between 38 and 46 °F (3 to 8 °C).

The days at San Antonio cool further during December. By the end of the month, the temperature has dropped around 5 °F (3 °C) below what it was at the start.

21 days 60 °F max. or more (16 °C)
15 days 40 °F min. or less (4 °C)

San Antonio averages 10 days in December when the thermometer reaches into the 70s °F (over 21 °C). Temperatures above 90 °F (32 °C) are not expected here this month.

The thermometer dips to freezing or below on an average of 5 nights. December can get as cold as 10 °F (-12 °C), but that rarely happens.

Rainy Weather iconRain

1.9 in total precipitation 49 mm
8 days of rain

Half the time, San Antonio receives 0.4 to 2 inches (10 to 62 mm) of rainfall in December. One in four years has drier weather, while another one in four is wetter.

Sunny Weather iconSun

48 % sunshine
10 days clear skies

The sun's rays reach the ground in San Antonio during 48 percent of daylight hours on average in December, for a total of 153 hours in the month. Typically on 10 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in December at San Antonio averages 10 hours and 17 minutes a day. The shortest days of the year, from around December 16th to 26th, last 10 hours and 16 minutes from sunrise to sunset.

Humid Weather iconHumidity

68 % December average humidity

The relative humidity in San Antonio during December usually peaks at 80 percent in the morning then drops to 50 percent by mid afternoon.

Local Time12 am3 am6 am9 am12 pm3 pm6 pm9 pm
Humidity % 76 79 80 75 57 50 56 70

Windy Weather iconWind

8.4 mph December wind speed average 13.5 kph

December is less windy than most other months in San Antonio.

Stormy Weather iconStorms

1 day rainfall of 0.5 inches (13 mm) or more
1 day with thunderstorms in December

Storms of any kind are infrequent during December at San Antonio.


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.

San Antonio Weather
Back to Top