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December Weather in San Francisco, Mexico

Last updated: August 27, 2025

In December, the average temperature in San Francisco, Mexico hovers around 17°C (63°F). Expect a range from a cool 5°C (41°F) to a warm 28°C (83°F). Rainfall can be expected with an average precipitation of 63 mm (2.5 in) spread over 13 days, contributing to a relatively high average humidity of 86%.

December Temperature in San Francisco

In December in San Francisco, the average temperature is 17°C (63°F), with maximums reaching 28°C (83°F) and minimums dropping as low as 5°C (41°F). This mild weather makes it an ideal time for outdoor activities and exploration.

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 17°C (63°F), with highs reaching up to 28°C (83°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec616365707270697070686562
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 63 mm (2.5 in) spread over 13 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 63 mm (2.5 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec8153465513229710415919720511363
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 86%. With an average temperature of 17°C (63°F), this humidity feels like a heavy blanket wrapping around you, making the air feel thick and slightly stifling for traveling, as every step requires more effort and even a gentle breeze feels refreshing amidst the muggy atmosphere.

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 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%73%59%53%54%55%61%71%77%78%82%86%
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 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For 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 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec10121414141414141413109
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 Weather16°C (62°F)81 mm (3.2 inches)84%very high
February Weather17°C (64°F)53 mm (2.1 inches)73%extreme
March Weather18°C (65°F)46 mm (1.8 inches)59%extreme
April Weather21°C (70°F)55 mm (2.2 inches)52%extreme
May Weather22°C (72°F)132 mm (5.2 inches)53%extreme
June Weather21°C (70°F)297 mm (11.7 inches)55%extreme
July Weather20°C (69°F)104 mm (4.1 inches)61%extreme
August Weather21°C (70°F)159 mm (6.2 inches)71%extreme
September Weather21°C (70°F)197 mm (7.8 inches)77%extreme
October Weather20°C (69°F)205 mm (8.1 inches)78%extreme
November Weather18°C (65°F)113 mm (4.4 inches)82%very high
December Weather17°C (63°F)63 mm (2.5 inches)86%very high

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