Last updated: June 24, 2025
In January, the average temperature in Santa Rosa, United States hovers around 9°C (49°F). Temperatures can dip as low as -2°C (28°F) and soar up to 24°C (75°F). Expect 139 mm (5.5 in) of precipitation spread over about 8 days, while the average humidity remains high at 86%. It's a month that beautifully balances cool days and refreshing moisture!
In January in Santa Rosa, the average temperature is 9°C (49°F). Maximum temperatures can reach 24°C (75°F), while minimums can drop as low as -2°C (28°F). Pack layers to accommodate the wide temperature range when traveling during this time.
In Santa Rosa in January, the total precipitation amount is 139 mm (5.5 in), which occurs over the course of 8 days.
In Santa Rosa in January, humidity is 86%. With an average temperature of 9°C (49°F), this humidity feels like a damp chill in the air, making travel uncomfortable as the moisture clings to your skin and thickens the atmosphere, creating a sense of heaviness that can tire you quickly.
In Santa Rosa in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Santa Rosa, you can check the information here.
UV Risk Categories
Weather in Santa Rosa varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Santa Rosa, focusing on differences in temperature, rainfall, humidity, and UV levels.
Temperature | Precipitation | Humidity | UV | |
---|---|---|---|---|
January Weather | 9°C (49°F) | 139 mm (5.5 inches) | 86% | moderate |
February Weather | 10°C (50°F) | 155 mm (6.1 inches) | 84% | moderate |
March Weather | 11°C (52°F) | 97 mm (3.8 inches) | 83% | high |
April Weather | 14°C (57°F) | 45 mm (1.8 inches) | 80% | very high |
May Weather | 17°C (62°F) | 27 mm (1.1 inches) | 80% | very high |
June Weather | 21°C (69°F) | 2 mm (0.1 inches) | 76% | extreme |
July Weather | 22°C (71°F) | 0 mm (0.0 inches) | 70% | extreme |
August Weather | 21°C (71°F) | 0 mm (0.0 inches) | 66% | very high |
September Weather | 20°C (69°F) | 2 mm (0.1 inches) | 68% | very high |
October Weather | 17°C (63°F) | 41 mm (1.6 inches) | 72% | high |
November Weather | 12°C (54°F) | 58 mm (2.3 inches) | 84% | moderate |
December Weather | 9°C (48°F) | 101 mm (4.0 inches) | 84% | moderate |