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December Weather in San Francisco, Mexico

Last updated: August 26, 2025

In December, the average temperature in San Francisco, Mexico hovers around 25°C (77°F), with nighttime lows of 18°C (66°F) and daytime highs reaching up to 29°C (85°F). Expect light precipitation of approximately 15 mm (0.6 in) over about 2 days, while the air remains comfortably humid at an average of 74%.

December Temperature in San Francisco

In December in San Francisco, the average temperature is 25°C (77°F), with maximums reaching 29°C (85°F) and minimums dipping to as low as 18°C (66°F). This pleasant weather makes it an ideal time for travelers to explore and enjoy outdoor activities in San Francisco.

December Weather in San Francisco: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in San Francisco, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Francisco, December typically has an average temperature of 25°C (77°F), with highs reaching up to 29°C (85°F) and lows dropping to around 18°C (66°F).
JanFebMarAprMayJunJulAugSepOctNovDec747474757881848483838177
Data source: Temperature data for San Francisco 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 San Francisco

In San Francisco in December, the precipitation amount is 15 mm (0.6 in) over the course of 2 days.

December Precipitation Trends in San Francisco

The chart displays monthly precipitation patterns in San Francisco, 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 San Francisco, December typically receives around 15 mm (0.6 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec2322003671302252661971915
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in San Francisco

In San Francisco in December humidity is 74%. With an average temperature of 25°C (77°F), this humidity feels like a warm, muggy blanket wrapping around you, making travel a bit more challenging as you find yourself sticky and in need of frequent breaks to hydrate and cool down.

December Average Humidity in San Francisco

This chart illustrates the average monthly humidity levels in San Francisco, 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 San Francisco is approximately 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec71%69%67%66%69%78%79%78%78%75%74%74%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in San Francisco

In San Francisco in December, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in San Francisco.

Maximum UV Index Levels in San Francisco for December

The chart shows the monthly maximum UV Index (UVI) for San Francisco 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 San Francisco typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec810121313131213121197
Data source: San Francisco 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 San Francisco Compares to Other Months

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

This table compares monthly weather conditions in San Francisco, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather24°C (75°F)23 mm (0.9 inches)71%very high
February Weather23°C (74°F)22 mm (0.9 inches)69%very high
March Weather23°C (74°F)0 mm (0.0 inches)67%extreme
April Weather24°C (76°F)0 mm (0.0 inches)66%extreme
May Weather25°C (78°F)3 mm (0.1 inches)69%extreme
June Weather27°C (81°F)67 mm (2.6 inches)78%extreme
July Weather29°C (84°F)130 mm (5.1 inches)79%extreme
August Weather29°C (84°F)225 mm (8.9 inches)78%extreme
September Weather28°C (83°F)266 mm (10.5 inches)78%extreme
October Weather28°C (83°F)197 mm (7.7 inches)75%extreme
November Weather27°C (81°F)19 mm (0.8 inches)74%very high
December Weather25°C (77°F)15 mm (0.6 inches)74%high

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