Last updated: August 27, 2025
In San Marcos, Mexico, the average temperature in December is a mild 12°C (55°F). However, temperatures can vary significantly, ranging from a chilly low of -7°C (19°F) to a warm high of 27°C (81°F). Expect some rainfall, with an average precipitation of 9 mm (0.3 in) over just 1 day. The atmosphere is quite humid, boasting an average humidity level of 84%.
In December in San Marcos, the average temperature is 12°C (55°F), with a maximum that can reach 27°C (81°F) and a minimum that can drop as low as -7°C (19°F). This wide range of temperatures makes it essential for travelers to pack both warm and cool clothing to stay comfortable during their visit.
In San Marcos in December, the precipitation amount is 9 mm (0.3 in) over the course of 1 day.
In San Marcos in December, humidity is 84%. With an average temperature of 12°C (55°F), this humidity feels like a thick blanket wrapping around you, making it a challenge for traveling as you might feel sticky and uncomfortable while exploring the sights.
In San Marcos in December, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in San Marcos.
UV Risk Categories
Weather in San Marcos varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Marcos, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 12°C (54°F) | 12 mm (0.5 inches) | 70% | very high |
| February Weather | 15°C (59°F) | 10 mm (0.4 inches) | 62% | extreme |
| March Weather | 18°C (64°F) | 11 mm (0.4 inches) | 53% | extreme |
| April Weather | 20°C (68°F) | 9 mm (0.4 inches) | 48% | extreme |
| May Weather | 22°C (73°F) | 15 mm (0.6 inches) | 52% | extreme |
| June Weather | 22°C (73°F) | 52 mm (2.1 inches) | 64% | extreme |
| July Weather | 20°C (69°F) | 136 mm (5.4 inches) | 73% | extreme |
| August Weather | 21°C (70°F) | 67 mm (2.6 inches) | 71% | extreme |
| September Weather | 18°C (65°F) | 125 mm (4.9 inches) | 82% | extreme |
| October Weather | 18°C (64°F) | 43 mm (1.7 inches) | 83% | extreme |
| November Weather | 15°C (59°F) | 10 mm (0.4 inches) | 82% | very high |
| December Weather | 12°C (55°F) | 9 mm (0.3 inches) | 84% | high |