December in San Antonio averages a daily high of 18°C with nights around 4.7°C. Expect roughly 8.1 wet days totalling 43.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit San Antonio is February–April.
Based on SAN ANTONIO INCARNATE WORD, TX US (5.5km), 1995–2024. 21 years of December data.