Last updated: August 27, 2025
In San Juan, Mexico, the average temperature in December hovers around 25°C (77°F), creating a pleasantly warm atmosphere. You'll experience a minimum of 17°C (63°F) and can reach up to 32°C (90°F) on hotter days. Be prepared for about 54 mm (2.1 in) of precipitation spread over 11 days, contributing to the region's 85% average humidity. Perfect for those who love a touch of tropical flair!
In December in San Juan, the average temperature is 25°C (77°F). Maximum can reach 32°C (90°F) and minimum can be as low as 17°C (63°F). This mild climate makes it an ideal time for outdoor activities and exploration.
In San Juan in December, the precipitation amount is 54 mm (2.1 in), occurring over the course of 11 days.
In San Juan in December, humidity is 85%. With an average temperature of 25°C (77°F), this humidity feels like a warm, heavy blanket wrapping around you, making every outdoor excursion feel both stifling and sticky, requiring frequent breaks in the shade to stay comfortable while exploring.
In San Juan 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 Juan.
UV Risk Categories
Weather in San Juan varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Juan, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 24°C (76°F) | 68 mm (2.7 inches) | 81% | very high |
| February Weather | 26°C (78°F) | 24 mm (0.9 inches) | 80% | extreme |
| March Weather | 27°C (81°F) | 20 mm (0.8 inches) | 76% | extreme |
| April Weather | 29°C (84°F) | 31 mm (1.2 inches) | 74% | extreme |
| May Weather | 30°C (87°F) | 45 mm (1.8 inches) | 74% | extreme |
| June Weather | 29°C (84°F) | 252 mm (9.9 inches) | 74% | extreme |
| July Weather | 30°C (85°F) | 54 mm (2.1 inches) | 79% | extreme |
| August Weather | 29°C (85°F) | 108 mm (4.2 inches) | 80% | extreme |
| September Weather | 28°C (84°F) | 184 mm (7.2 inches) | 79% | extreme |
| October Weather | 28°C (82°F) | 235 mm (9.3 inches) | 81% | extreme |
| November Weather | 26°C (79°F) | 138 mm (5.5 inches) | 84% | very high |
| December Weather | 25°C (77°F) | 54 mm (2.1 inches) | 85% | very high |