Last updated: June 24, 2025
In December, the average temperature in San Antonio, United States hovers around 17°C (64°F), providing a mild yet refreshing climate. Expect a minimum of 0°C (33°F) and a maximum of 29°C (84°F), so be prepared for a variety of temperatures. During this month, anticipate around 70 mm (2.8 in) of precipitation spread over 7 days, contributing to an average humidity level of 84%. Enjoy the unique weather patterns that this month brings!
In December in San Antonio, the average temperature is 17°C (64°F). Maximum temperatures can reach 29°C (84°F), while minimums can drop as low as 0°C (33°F). This diverse temperature range makes San Antonio an ideal destination for travelers seeking both warmth and cooler experiences.
In San Antonio in December, the precipitation amount is 70 mm (2.8 in) over a span of 7 days.
In San Antonio in December, humidity is 84%. With an average temperature of 17°C (64°F), this humidity feels like a warm embrace, making it essential for travelers to stay hydrated and take frequent breaks in the shade to avoid feeling overly sticky and drained.
In San Antonio in December, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in San Antonio.
UV Risk Categories
Weather in San Antonio varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Antonio, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 16°C (60°F) | 43 mm (1.7 inches) | 83% | high |
| February Weather | 19°C (66°F) | 69 mm (2.7 inches) | 80% | very high |
| March Weather | 20°C (68°F) | 20 mm (0.8 inches) | 75% | very high |
| April Weather | 23°C (73°F) | 77 mm (3.0 inches) | 70% | extreme |
| May Weather | 25°C (78°F) | 123 mm (4.8 inches) | 68% | extreme |
| June Weather | 27°C (81°F) | 223 mm (8.8 inches) | 75% | extreme |
| July Weather | 27°C (81°F) | 276 mm (10.8 inches) | 79% | extreme |
| August Weather | 28°C (82°F) | 247 mm (9.7 inches) | 81% | extreme |
| September Weather | 27°C (81°F) | 189 mm (7.4 inches) | 83% | extreme |
| October Weather | 25°C (77°F) | 82 mm (3.2 inches) | 81% | very high |
| November Weather | 20°C (68°F) | 49 mm (1.9 inches) | 82% | high |
| December Weather | 17°C (64°F) | 70 mm (2.8 inches) | 84% | moderate |