The highest day temperature in December 2025 was 72°F. The lowest night temperature was 54°F. The average values for day and night temperatures during December were 67.2°F и 57.7°F respectivly.

The average sea surface temperature in December 2025 for San Antonio was 61.3°F. The maximum and minimum values were 57.4°F and 65.2°F respectively.

Most of the days in December are sunny but you can also expect cloudy and gloomy days.

Precipitation total in December for San Antonio is 0.0 in. It makes december one of the least rainy months of the year.

The average wind speed in December is 8.4 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for San Antonio in December is 12.9 hours.