January Weather in San Jose, United States

Last updated: June 24, 2025

In January, the average temperature in San Jose, United States hovers around 8°C (47°F). Expect chilly lows reaching -5°C (23°F), while sunny days can warm up to a pleasant 22°C (72°F). Rainfall is moderate, with about 23 mm (0.9 in) spread over 4 days, contributing to an average humidity of 81%. Stay prepared for varying weather conditions!

January Temperature in San Jose

In January in San Jose, the average temperature is 8°C (47°F). The maximum can reach 22°C (72°F) and the minimum can be as low as -5°C (23°F). Travelers should prepare for a wide range of temperatures and pack accordingly.

January Weather in San Jose: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in San Jose, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Jose, January typically has an average temperature of 8°C (47°F), with highs reaching up to 22°C (72°F) and lows dropping to around -5°C (23°F).

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

January Precipitation in San Jose

In San Jose in January, the total precipitation amount is 23 mm (0.9 in) over a span of 4 days.

January Precipitation Trends in San Jose

The chart displays monthly precipitation patterns in San Jose, 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 San Jose, January typically receives around 23 mm (0.9 inches) of precipitation spread over approximately 4 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 San Jose

In San Jose in January humidity is 81%. With an average temperature of 8°C (47°F), this humidity feels like a palpable heaviness in the air, making outdoor exploration feel damp and chilly, requiring travelers to bundle up and prepare for a brisk experience.

January Average Humidity in San Jose

This chart illustrates the average monthly humidity levels in San Jose, 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 San Jose is approximately 81%, 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 San Jose

In San Jose in January, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in San Jose.

Maximum UV Index Levels in San Jose for January

The chart shows the monthly maximum UV Index (UVI) for San Jose 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 San Jose typically reaches 5, which falls under the moderate exposure category.

Data source: San Jose 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 San Jose Compares to Other Months

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

This table compares monthly weather conditions in San Jose, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	8°C (47°F)	23 mm (0.9 inches)	81%	moderate
February Weather	10°C (50°F)	32 mm (1.2 inches)	82%	high
March Weather	15°C (59°F)	16 mm (0.6 inches)	68%	very high
April Weather	20°C (68°F)	2 mm (0.1 inches)	55%	extreme
May Weather	24°C (76°F)	3 mm (0.1 inches)	45%	extreme
June Weather	30°C (86°F)	4 mm (0.2 inches)	37%	extreme
July Weather	30°C (86°F)	45 mm (1.8 inches)	43%	extreme
August Weather	29°C (85°F)	22 mm (0.9 inches)	53%	extreme
September Weather	26°C (79°F)	28 mm (1.1 inches)	66%	extreme
October Weather	20°C (68°F)	13 mm (0.5 inches)	72%	very high
November Weather	14°C (58°F)	20 mm (0.8 inches)	81%	high
December Weather	9°C (48°F)	25 mm (1.0 inches)	84%	moderate