Last updated: June 24, 2025
In Alta Sierra, United States, the average temperature in December hovers around 4°C (40°F). Expect a wide range of temperatures, with minimums dipping to -12°C (10°F) and maximums reaching up to 21°C (70°F). During this month, you can anticipate 70 mm (2.8 in) of precipitation over 7 days, combined with an average humidity of 76%, creating a crisp and potentially damp atmosphere.
In December in Alta Sierra, the average temperature is 4°C (40°F). Maximum temperatures can reach 21°C (70°F), while the minimum can drop as low as -12°C (10°F). Be prepared for a wide range of temperatures when traveling during this month!
In Alta Sierra in December, the precipitation amount is 70 mm (2.8 in) over a span of 7 days.
In Alta Sierra in December humidity is 76%. With an average temperature of 4°C (40°F), this humidity feels like a chilly embrace, making travel feel damp and slightly clammy, as the cool air clings to your skin, requiring extra layers to stay comfortable while experiencing the sights.
In Alta Sierra in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Alta Sierra for better planning.
UV Risk Categories
Weather in Alta Sierra varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Alta Sierra, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 4°C (39°F) | 102 mm (4.0 inches) | 78% | moderate |
| February Weather | 4°C (40°F) | 84 mm (3.3 inches) | 82% | high |
| March Weather | 6°C (43°F) | 89 mm (3.5 inches) | 75% | very high |
| April Weather | 10°C (51°F) | 41 mm (1.6 inches) | 68% | very high |
| May Weather | 14°C (57°F) | 32 mm (1.2 inches) | 57% | extreme |
| June Weather | 20°C (69°F) | 5 mm (0.2 inches) | 52% | extreme |
| July Weather | 24°C (76°F) | 5 mm (0.2 inches) | 46% | extreme |
| August Weather | 23°C (74°F) | 3 mm (0.1 inches) | 39% | extreme |
| September Weather | 20°C (68°F) | 5 mm (0.2 inches) | 48% | very high |
| October Weather | 14°C (57°F) | 11 mm (0.4 inches) | 59% | very high |
| November Weather | 9°C (48°F) | 34 mm (1.3 inches) | 72% | moderate |
| December Weather | 4°C (40°F) | 70 mm (2.8 inches) | 76% | moderate |