Last updated: June 24, 2025
In December, the average temperature in Mountain View, United States hovers around 1°C (34°F). Expect a minimum chill of -19°C (-1°F) and the chance to experience a warm maximum of 22°C (72°F). This month sees 14 mm (0.6 in) of precipitation over just 3 days, accompanied by high humidity levels averaging around 89%.
In December in Mountain View, the average temperature is 1°C (34°F). Maximum temperatures can reach 22°C (72°F), while minimums can drop as low as -19°C (-1°F). Be prepared for a wide range of temperatures if you plan to travel during this month.
In Mountain View in December, the precipitation amount is 14 mm (0.6 in) accumulated over the course of 3 days.
In Mountain View in December humidity is 89%. With an average temperature of 1°C (34°F), this humidity feels like a chilling dampness that seeps into your bones, making travel uncomfortable and requiring extra layers to combat the cold and moisture.
In Mountain View 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 Mountain View for better planning.
UV Risk Categories
Weather in Mountain View varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Mountain View, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (31°F) | 23 mm (0.9 inches) | 88% | moderate |
| February Weather | -1°C (30°F) | 29 mm (1.1 inches) | 87% | high |
| March Weather | 4°C (40°F) | 57 mm (2.3 inches) | 81% | very high |
| April Weather | 8°C (47°F) | 55 mm (2.2 inches) | 76% | extreme |
| May Weather | 13°C (56°F) | 111 mm (4.4 inches) | 66% | extreme |
| June Weather | 20°C (68°F) | 48 mm (1.9 inches) | 58% | extreme |
| July Weather | 23°C (74°F) | 43 mm (1.7 inches) | 52% | extreme |
| August Weather | 22°C (72°F) | 35 mm (1.4 inches) | 56% | extreme |
| September Weather | 19°C (66°F) | 29 mm (1.2 inches) | 65% | very high |
| October Weather | 9°C (49°F) | 37 mm (1.5 inches) | 76% | high |
| November Weather | 5°C (41°F) | 24 mm (1.0 inches) | 82% | moderate |
| December Weather | 1°C (34°F) | 14 mm (0.6 inches) | 89% | moderate |