Last updated: June 24, 2025
In San Rafael, United States, the average temperature in December hovers around 0°C (32°F). Expect chilly days, with minimum temperatures dropping to -22°C (-7°F) and maximums reaching a more pleasant 16°C (61°F). During this month, the region receives about 21 mm (0.8 in) of precipitation over 4 days, contributing to an average humidity level of 82%. Stay warm and prepared for the damp chill!
In December in San Rafael, the average temperature is 0°C (32°F), with maximums reaching 16°C (61°F) and minimums dipping as low as -22°C (-7°F). Travelers should be prepared for a wide range of temperatures, from chilly conditions to milder days.
In San Rafael in December, the precipitation amount is 21 mm (0.8 in) over a span of 4 days.
In San Rafael in December, humidity is 82%. With an average temperature of 0°C (32°F), this humidity feels like an icy breath enveloping you, making each step outdoors a challenge as the cold dampness seeps into your clothes, chilling you to the bone and sapping your energy while traveling.
In San Rafael 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 San Rafael for better planning.
UV Risk Categories
Weather in San Rafael varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Rafael, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -2°C (29°F) | 24 mm (1.0 inches) | 81% | moderate |
| February Weather | 1°C (34°F) | 23 mm (0.9 inches) | 83% | high |
| March Weather | 6°C (43°F) | 31 mm (1.2 inches) | 71% | very high |
| April Weather | 10°C (51°F) | 20 mm (0.8 inches) | 61% | extreme |
| May Weather | 15°C (60°F) | 16 mm (0.6 inches) | 48% | extreme |
| June Weather | 22°C (71°F) | 12 mm (0.5 inches) | 36% | extreme |
| July Weather | 22°C (72°F) | 58 mm (2.3 inches) | 37% | extreme |
| August Weather | 21°C (70°F) | 36 mm (1.4 inches) | 46% | extreme |
| September Weather | 18°C (65°F) | 32 mm (1.3 inches) | 62% | extreme |
| October Weather | 11°C (53°F) | 23 mm (0.9 inches) | 74% | very high |
| November Weather | 6°C (42°F) | 14 mm (0.6 inches) | 82% | high |
| December Weather | 0°C (32°F) | 21 mm (0.8 inches) | 82% | moderate |