Last updated: August 27, 2025
In December, the average temperature in San Antonio, Mexico hovers around 19°C (66°F). Expect a comfortable range, with minimum temperatures dipping to 8°C (47°F) and highs reaching up to 30°C (87°F). You'll likely experience some light rain, with an average precipitation of 16 mm (0.6 in) spread over 2 days. Don't forget, humidity levels can be high, averaging around 80%.
In December in San Antonio, the average temperature is 19°C (66°F). Maximums can reach 30°C (87°F), and minimums can be as low as 8°C (47°F). It's a pleasant time to visit, offering a comfortable climate for exploring and enjoying outdoor activities.
In San Antonio in December, the precipitation amount is 16 mm (0.6 in) over a period of 2 days.
In San Antonio in December humidity is 80%. With an average temperature of 19°C (66°F), this humidity feels like a warm, thick blanket wrapping around you, making outdoor activities feel more strenuous and sticky, which can ultimately dampen the experience of traveling.
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 | 18°C (64°F) | 13 mm (0.5 inches) | 74% | high |
| February Weather | 18°C (65°F) | 9 mm (0.4 inches) | 67% | very high |
| March Weather | 20°C (68°F) | 5 mm (0.2 inches) | 60% | very high |
| April Weather | 23°C (73°F) | 0 mm (0.0 inches) | 51% | extreme |
| May Weather | 25°C (78°F) | 0 mm (0.0 inches) | 47% | extreme |
| June Weather | 29°C (84°F) | 18 mm (0.7 inches) | 50% | extreme |
| July Weather | 31°C (88°F) | 36 mm (1.4 inches) | 70% | extreme |
| August Weather | 31°C (88°F) | 73 mm (2.9 inches) | 81% | extreme |
| September Weather | 30°C (86°F) | 77 mm (3.0 inches) | 82% | extreme |
| October Weather | 28°C (83°F) | 20 mm (0.8 inches) | 78% | very high |
| November Weather | 24°C (75°F) | 28 mm (1.1 inches) | 78% | high |
| December Weather | 19°C (66°F) | 16 mm (0.6 inches) | 80% | moderate |