Last updated: June 24, 2025
In December, the average temperature in San Jose, United States hovers around 2°C (36°F), presenting a chilly atmosphere. While temperatures can dip as low as -20°C (-4°F), they can also rise to a pleasant 20°C (68°F). Expect some rain, with an average precipitation amount of 53 mm (2.1 in) spread over 8 days. The average humidity sits at a notable 84%, adding to the cool, damp feel of the season.
In December in San Jose, the average temperature is 2°C (36°F). The maximum can reach 20°C (68°F), while the minimum can drop as low as -20°C (-4°F). Be prepared for a wide range of temperatures if you plan to travel during this time.
In San Jose in December, the total precipitation amount is 53 mm (2.1 in) over the course of 8 days.
In San Jose in December, humidity is 84%. With an average temperature of 2°C (36°F), this humidity feels like a cold, damp blanket wrapping around you, making outdoor activities less inviting and requiring extra layers to stay comfortable while traveling.
In San Jose in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in San Jose, you can visit Hourly UV Index in San Jose.
UV Risk Categories
Weather in San Jose varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Jose, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -2°C (28°F) | 67 mm (2.6 inches) | 82% | moderate |
| February Weather | -1°C (31°F) | 69 mm (2.7 inches) | 83% | moderate |
| March Weather | 6°C (43°F) | 121 mm (4.8 inches) | 84% | high |
| April Weather | 11°C (52°F) | 121 mm (4.8 inches) | 85% | very high |
| May Weather | 18°C (65°F) | 152 mm (6.0 inches) | 79% | very high |
| June Weather | 24°C (75°F) | 131 mm (5.2 inches) | 82% | extreme |
| July Weather | 25°C (77°F) | 115 mm (4.5 inches) | 80% | very high |
| August Weather | 23°C (74°F) | 97 mm (3.8 inches) | 81% | very high |
| September Weather | 21°C (71°F) | 65 mm (2.6 inches) | 80% | very high |
| October Weather | 14°C (57°F) | 115 mm (4.5 inches) | 82% | high |
| November Weather | 5°C (41°F) | 64 mm (2.5 inches) | 88% | moderate |
| December Weather | 2°C (36°F) | 53 mm (2.1 inches) | 84% | low |