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December Weather in Palo Alto, United States

Last updated: June 24, 2025

In December, the average temperature in Palo Alto, United States hovers around 1°C (35°F). Expect a chilly range with minimums dipping to -16°C (4°F) and maximums peaking at 17°C (62°F). This month also brings about 93 mm (3.7 in) of precipitation over 11 days, contributing to a notably high average humidity level of 85%. Be prepared for a mix of cold and wet weather!

December Temperature in Palo Alto

In December in Palo Alto, the average temperature is 1°C (35°F). Maximum temperatures can reach 17°C (62°F), while minimums can drop as low as -16°C (4°F). Travelers should be prepared for a wide range of temperatures and dress in layers to stay comfortable throughout the day.

December Weather in Palo Alto: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Palo Alto, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Palo Alto, December typically has an average temperature of 1°C (35°F), with highs reaching up to 17°C (62°F) and lows dropping to around -16°C (4°F).
JanFebMarAprMayJunJulAugSepOctNovDec303339506169757266564135
Data source: Temperature data for Palo Alto 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.

December Precipitation in Palo Alto

In Palo Alto in December, the precipitation amount is 93 mm (3.7 in) over the course of 11 days, indicating that rain is expected to be fairly frequent during that time.

December Precipitation Trends in Palo Alto

The chart displays monthly precipitation patterns in Palo Alto, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Palo Alto, December typically receives around 93 mm (3.7 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec74106961111331181631551171179993
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Palo Alto

In Palo Alto in December humidity is 85%. With an average temperature of 1°C (35°F), this humidity feels like a chilly blanket wrapping around you, making outdoor adventures damp and uncomfortable, especially for travelers unprepared for such a heavy and cold atmosphere.

December Average Humidity in Palo Alto

This chart illustrates the average monthly humidity levels in Palo Alto, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Palo Alto is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%85%85%83%75%74%65%62%66%79%87%85%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Palo Alto

In Palo Alto in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Palo Alto, you can visit Hourly UV Index in Palo Alto.

Maximum UV Index Levels in Palo Alto for December

The chart shows the monthly maximum UV Index (UVI) for Palo Alto in December, 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 December, the maximum UV index in Palo Alto typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: Palo Alto December 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 December Weather in Palo Alto Compares to Other Months

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

This table compares monthly weather conditions in Palo Alto, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (30°F)74 mm (2.9 inches)87%moderate
February Weather1°C (33°F)106 mm (4.2 inches)85%moderate
March Weather4°C (39°F)96 mm (3.8 inches)85%high
April Weather10°C (50°F)111 mm (4.4 inches)83%very high
May Weather16°C (61°F)133 mm (5.2 inches)75%very high
June Weather21°C (69°F)118 mm (4.6 inches)73%very high
July Weather24°C (75°F)163 mm (6.4 inches)65%very high
August Weather22°C (73°F)155 mm (6.1 inches)62%very high
September Weather19°C (67°F)117 mm (4.6 inches)66%very high
October Weather13°C (57°F)117 mm (4.6 inches)79%high
November Weather5°C (42°F)99 mm (3.9 inches)87%moderate
December Weather1°C (35°F)93 mm (3.7 inches)85%low

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