Last updated: August 27, 2025
In December, the average temperature in San Antonio, Mexico is a pleasant 17°C (62°F). Expect a range of temperatures, with minimums dipping to 2°C (36°F) and maximums soaring to 35°C (95°F). You'll experience an average humidity of 80%, along with 21 mm (0.8 in) of precipitation across 3 days.
In December in San Antonio, the average temperature is 17°C (62°F). Maximums can reach 35°C (95°F) and minimums can be as low as 2°C (36°F). This variation in temperature makes San Antonio a destination that requires layered clothing and preparations for both warm and cooler periods during your trip.
In San Antonio in December, the precipitation amount is 21 mm (0.8 in) over a period of 3 days.
In San Antonio in December, humidity is 80%. With an average temperature of 17°C (62°F), this humidity feels like a heavy blanket wrapping around you, making travel sticky and uncomfortable, and often leaving you longing for a refreshing breeze.
In San Antonio in December, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in San Antonio, you can refer to this 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 | 15°C (59°F) | 24 mm (1.0 inches) | 75% | high |
| February Weather | 17°C (64°F) | 13 mm (0.5 inches) | 70% | very high |
| March Weather | 22°C (71°F) | 24 mm (0.9 inches) | 65% | very high |
| April Weather | 24°C (76°F) | 40 mm (1.6 inches) | 59% | extreme |
| May Weather | 27°C (81°F) | 68 mm (2.7 inches) | 66% | extreme |
| June Weather | 29°C (84°F) | 86 mm (3.4 inches) | 71% | extreme |
| July Weather | 29°C (85°F) | 82 mm (3.2 inches) | 57% | extreme |
| August Weather | 30°C (87°F) | 15 mm (0.6 inches) | 58% | extreme |
| September Weather | 27°C (81°F) | 110 mm (4.3 inches) | 72% | extreme |
| October Weather | 24°C (75°F) | 49 mm (1.9 inches) | 76% | very high |
| November Weather | 19°C (67°F) | 24 mm (0.9 inches) | 81% | high |
| December Weather | 17°C (62°F) | 21 mm (0.8 inches) | 80% | high |