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January Weather in Santa Rosa, United States

Last updated: June 24, 2025

In Santa Rosa, United States, the average temperature in January hovers around 17°C (62°F). During this time, you may experience a range from a chilly -1°C (30°F) to a warm 35°C (94°F). Expect about 24 mm (1.0 in) of precipitation spread over 5 days, with an average humidity of 83%, creating a distinctly damp atmosphere.

January Temperature in Santa Rosa

In January in Santa Rosa, the average temperature is 17°C (62°F). Maximum can reach 35°C (94°F) and minimum can be as low as -1°C (30°F). Visitors should be prepared for a wide range of temperatures, making it essential to pack accordingly for both warm and cool weather.

January Weather in Santa Rosa: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Santa Rosa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Santa Rosa, January typically has an average temperature of 17°C (62°F), with highs reaching up to 35°C (94°F) and lows dropping to around -1°C (30°F).
JanFebMarAprMayJunJulAugSepOctNovDec626572768284868783776964
Data source: Temperature data for Santa Rosa generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Santa Rosa

In Santa Rosa in January, the precipitation amount is 24 mm (1.0 in) spread over the course of 5 days.

January Precipitation Trends in Santa Rosa

The chart displays monthly precipitation patterns in Santa Rosa, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Santa Rosa, January typically receives around 24 mm (1.0 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec2421353081919433114653023
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Santa Rosa

In Santa Rosa in January, humidity is 83%. With an average temperature of 17°C (62°F), this humidity feels like traveling through a thick blanket of warmth, making every step feel heavy and inviting frequent breaks to cool down and hydrate.

January Average Humidity in Santa Rosa

This chart illustrates the average monthly humidity levels in Santa Rosa, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Santa Rosa is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec83%79%76%77%80%73%66%65%73%76%80%86%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Santa Rosa

In Santa Rosa in January, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Santa Rosa, you can refer to this Hourly UV Index in Santa Rosa.

Maximum UV Index Levels in Santa Rosa for January

The chart shows the monthly maximum UV Index (UVI) for Santa Rosa in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Santa Rosa typically reaches 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec69101112121212111076
Data source: Santa Rosa January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How January Weather in Santa Rosa Compares to Other Months

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.

This table compares monthly weather conditions in Santa Rosa, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather17°C (62°F)24 mm (1.0 inches)83%high
February Weather18°C (65°F)21 mm (0.8 inches)79%very high
March Weather22°C (72°F)35 mm (1.4 inches)76%very high
April Weather25°C (77°F)30 mm (1.2 inches)77%extreme
May Weather28°C (82°F)81 mm (3.2 inches)80%extreme
June Weather29°C (85°F)91 mm (3.6 inches)73%extreme
July Weather30°C (86°F)94 mm (3.7 inches)66%extreme
August Weather30°C (87°F)33 mm (1.3 inches)65%extreme
September Weather28°C (83°F)114 mm (4.5 inches)73%extreme
October Weather25°C (77°F)64 mm (2.5 inches)76%very high
November Weather21°C (69°F)30 mm (1.2 inches)80%high
December Weather18°C (65°F)23 mm (0.9 inches)86%high

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