Last updated: March 2, 2024
The weather in Grass Valley, United States, during December is characterized by an average temperature of 7°C (44°F). Highs can soar to 19°C (66°F), while lows may dip to -2°C (28°F). Typically, the humidity level in Grass Valley throughout December hovers around 83%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In December, Grass Valley averages 215 mm (8.4 inches) of rainfall, typically over the course of 11 rainy days. The month enjoys an average of 9 hours 26 minutes of daylight, with the sun shining for approximately 6 hours 0 minutes each day. Additionally, there is a 37% probability of sunny days during this period.
Precipitation
Rainy days
Sunshine hours
Chance of sun
In December, the UV Index in Grass Valley reaches a maximum of 3, indicating a level of Moderate exposure. The most intense UV radiation typically occurs between 12:00 and 14:00, during which unprotected skin may burn in as little as 30 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 | 1 | 2 | 2 | 3 | 2 | 2 | 1 | 1 | 0 | 0 | 0 |
| Exposure | Low | Moderate | Low | ||||||||||
| Time to burn | 45 min | 30 min | 45 min | ||||||||||