January Weather in Grass Valley, United States

Last updated: June 24, 2025

In January, the average temperature in Grass Valley, United States is a crisp 7°C (45°F). Expect chilly nights with minimums dipping down to -5°C (24°F), while daytime highs can reach a pleasant 21°C (71°F). Be prepared for some rain, as the area receives about 269 mm (10.6 in) of precipitation over 12 days. With an average humidity of 84%, this month can feel quite damp, so pack accordingly!

January Temperature in Grass Valley

In January in Grass Valley, the average temperature is 7°C (45°F). Maximums can reach 21°C (71°F) and minimums can drop as low as -5°C (24°F). Be prepared for a wide range of temperatures while traveling!

January Weather in Grass Valley: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Grass Valley, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Grass Valley, January typically has an average temperature of 7°C (45°F), with highs reaching up to 21°C (71°F) and lows dropping to around -5°C (24°F).

Data source: Temperature data for Grass Valley generated using information from the Copernicus Climate Change Service.

January Precipitation in Grass Valley

In Grass Valley in January, the precipitation amount is 269 mm (10.6 in) spread over a period of 12 days.

January Precipitation Trends in Grass Valley

The chart displays monthly precipitation patterns in Grass Valley, 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 Grass Valley, January typically receives around 269 mm (10.6 inches) of precipitation spread over approximately 12 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Grass Valley

In Grass Valley in January, humidity is 84%. With an average temperature of 7°C (45°F), this humidity feels like a damp chill that seeps into your bones, making travel uncomfortable and necessitating extra layers to stay warm while exploring the sights.

January Average Humidity in Grass Valley

This chart illustrates the average monthly humidity levels in Grass Valley, 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 Grass Valley is approximately 84%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Grass Valley

In Grass Valley 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 Grass Valley, you can check the information here.

Maximum UV Index Levels in Grass Valley for January

The chart shows the monthly maximum UV Index (UVI) for Grass Valley 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 Grass Valley typically reaches 3, which falls under the moderate exposure category.

Data source: Grass Valley 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 Grass Valley Compares to Other Months

Weather in Grass Valley varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Grass Valley, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Grass Valley, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	7°C (45°F)	269 mm (10.6 inches)	84%	moderate
February Weather	8°C (46°F)	279 mm (11.0 inches)	84%	moderate
March Weather	9°C (48°F)	267 mm (10.5 inches)	83%	high
April Weather	13°C (55°F)	129 mm (5.1 inches)	81%	very high
May Weather	17°C (62°F)	76 mm (3.0 inches)	74%	very high
June Weather	22°C (72°F)	13 mm (0.5 inches)	64%	extreme
July Weather	26°C (79°F)	1 mm (0.0 inches)	44%	extreme
August Weather	25°C (77°F)	2 mm (0.1 inches)	36%	very high
September Weather	21°C (70°F)	23 mm (0.9 inches)	44%	very high
October Weather	15°C (60°F)	78 mm (3.1 inches)	65%	high
November Weather	10°C (51°F)	157 mm (6.2 inches)	84%	moderate
December Weather	7°C (44°F)	215 mm (8.4 inches)	83%	moderate