Last updated: August 27, 2025
In December, the average temperature in San Marcos, Mexico is a comfortable 16°C (62°F). Expect temperatures to range from a chilly 3°C (38°F) at night to a warm 30°C (85°F) during the day. During this time, you can anticipate 15 mm (0.6 in) of precipitation over about 3 days, with an average humidity level of 74%. Stay prepared for a mix of pleasant and wet weather!
In December in San Marcos, the average temperature is 16°C (62°F). Maximum temperatures can reach 30°C (85°F), while minimums can drop to as low as 3°C (38°F). Pack accordingly to enjoy a comfortable trip while exploring the diverse climate conditions!
In San Marcos in December, the precipitation amount is 15 mm (0.6 in) over the course of 3 days.
In San Marcos in December, humidity is 74%. With an average temperature of 16°C (62°F), this humidity feels like a warm, heavy blanket enveloping you, making it slightly uncomfortable for traveling as it can lead to a sticky sensation that may sap your energy during outdoor activities.
In San Marcos in December, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to 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 | 16°C (62°F) | 13 mm (0.5 inches) | 64% | very high |
| February Weather | 17°C (64°F) | 21 mm (0.8 inches) | 57% | extreme |
| March Weather | 20°C (68°F) | 3 mm (0.1 inches) | 46% | extreme |
| April Weather | 21°C (70°F) | 1 mm (0.0 inches) | 42% | extreme |
| May Weather | 23°C (73°F) | 14 mm (0.5 inches) | 51% | extreme |
| June Weather | 23°C (73°F) | 113 mm (4.4 inches) | 74% | extreme |
| July Weather | 21°C (70°F) | 252 mm (9.9 inches) | 79% | extreme |
| August Weather | 21°C (71°F) | 248 mm (9.8 inches) | 81% | extreme |
| September Weather | 21°C (70°F) | 267 mm (10.5 inches) | 84% | extreme |
| October Weather | 21°C (70°F) | 99 mm (3.9 inches) | 75% | extreme |
| November Weather | 19°C (66°F) | 19 mm (0.7 inches) | 71% | very high |
| December Weather | 16°C (62°F) | 15 mm (0.6 inches) | 74% | very high |