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January Weather in San Jose, United States

Last updated: June 24, 2025

In January, the average temperature in San Jose, United States hovers around -2°C (28°F). However, temperatures can drop as low as -28°C (-18°F) or soar up to 16°C (62°F). Expect 67 mm (2.6 in) of precipitation spread over 9 days, with an average humidity of 82% providing a chilly atmosphere.

January Temperature in San Jose

In January in San Jose, the average temperature is -2°C (28°F), with maximums reaching up to 16°C (62°F) and minimums dipping as low as -28°C (-18°F). Travelers should be prepared for a wide range of temperatures and dress in layers to stay comfortable while exploring the area.

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 -2°C (28°F), with highs reaching up to 16°C (62°F) and lows dropping to around -28°C (-18°F).
JanFebMarAprMayJunJulAugSepOctNovDec283143526574777470574135
Data source: Temperature data for San Jose 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 San Jose

In San Jose in January, the total precipitation amount is 67 mm (2.6 in), occurring over a span of 9 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 67 mm (2.6 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec676912112115213111597651156453
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in San Jose

In San Jose in January, humidity is 82%. With an average temperature of -2°C (28°F), this humidity feels like an icy shroud enveloping you, making every breath feel crisp and biting as you navigate through a winter wonderland, each step a reminder of the contrast between the cold air and the heavy moisture lingering in the atmosphere.

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 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%83%84%85%79%82%80%81%80%82%88%84%
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 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 San Jose, you can check the information here.

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 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357810111098642
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.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)67 mm (2.6 inches)82%moderate
February Weather-1°C (31°F)69 mm (2.7 inches)83%moderate
March Weather6°C (43°F)121 mm (4.8 inches)84%high
April Weather11°C (52°F)121 mm (4.8 inches)85%very high
May Weather18°C (65°F)152 mm (6.0 inches)79%very high
June Weather24°C (75°F)131 mm (5.2 inches)82%extreme
July Weather25°C (77°F)115 mm (4.5 inches)80%very high
August Weather23°C (74°F)97 mm (3.8 inches)81%very high
September Weather21°C (71°F)65 mm (2.6 inches)80%very high
October Weather14°C (57°F)115 mm (4.5 inches)82%high
November Weather5°C (41°F)64 mm (2.5 inches)88%moderate
December Weather2°C (36°F)53 mm (2.1 inches)84%low

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