Last updated: March 2, 2024
The weather in Keystone, United States, during December is characterized by an average temperature of -11°C (13°F). Highs can soar to 4°C (40°F), while lows may dip to -26°C (-15°F). Typically, the humidity level in Keystone throughout December hovers around 89%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In December, Keystone averages 43 mm (1.7 inches) of rainfall, typically over the course of 10 rainy days. The month enjoys an average of 9 hours 25 minutes of daylight, with the sun shining for approximately 7 hours 39 minutes each day. Additionally, there is a 53% probability of sunny days during this period.
Precipitation
Rainy days
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Chance of sun
In December, the UV Index in Keystone reaches a maximum of 4, indicating a level of Moderate exposure. The most intense UV radiation typically occurs between 11:00 and 13:00, 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 | 2 | 2 | 3 | 3 | 3 | 2 | 1 | 1 | 0 | 0 | 0 |
| Exposure | Low | Moderate | Low | ||||||||||
| Time to burn | 45 min | 30 min | 45 min | ||||||||||