San Antonio, Texas weather in December

Averages from 2021–2025 (155 days of record).

Average high: 69°F
Average low: 51°F
Rainy days: ~7 per month
Total precipitation: 1.7 in
Warmest recorded: 86°F
Coldest recorded: 17°F

Expect December days in San Antonio, Texas to top out around 69°F and cool to about 51°F overnight, with roughly 7 days of measurable rain across the month. In recent years December has ranged from 17°F to 86°F.

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Current San Antonio, Texas forecast → · Historical data by Open-Meteo (ERA5).