Last updated: March 2, 2024
The weather in San Juan, United States, during December is characterized by an average temperature of 18°C (64°F). Highs can soar to 32°C (89°F), while lows may dip to 3°C (39°F). Typically, the humidity level in San Juan throughout December hovers around 86%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In December, San Juan averages 21 mm (0.8 inches) of rainfall, typically over the course of 3 rainy days. The month enjoys an average of 10 hours 30 minutes of daylight, with the sun shining for approximately 7 hours 55 minutes each day. Additionally, there is a 51% probability of sunny days during this period.
Precipitation
Rainy days
Sunshine hours
Chance of sun
In December, the UV Index in San Juan reaches a maximum of 6, indicating a level of High exposure. The most intense UV radiation typically occurs between 12:00 and 14:00, during which unprotected skin may burn in as little as 25 minutes.
| 07:00 | 08:00 | 09:00 | 10:00 | 11:00 | 12:00 | 13:00 | 14:00 | 15:00 | 16:00 | 17:00 | 18:00 | 19:00 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UVI | 0 | 1 | 2 | 3 | 5 | 6 | 5 | 4 | 3 | 1 | 1 | 0 | 0 |
| Exposure | Low | Moderate | High | Moderate | Low | ||||||||
| Time to burn | 45 min | 30 min | 25 min | 30 min | 45 min | ||||||||