nomadseason

December Weather in San Francisco, Mexico

Last updated: August 27, 2025

In December, the average temperature in San Francisco, Mexico is a pleasant 18°C (64°F). However, temperatures can vary significantly, dipping to a minimum of 4°C (39°F) and soaring up to a maximum of 30°C (87°F). Expect 62 mm (2.4 in) of precipitation spread over 9 days, alongside a high average humidity of 91%.

December Temperature in San Francisco

In December in San Francisco, the average temperature is 18°C (64°F). Maximums can reach 30°C (87°F), while minimums can dip as low as 4°C (39°F). It's advisable to prepare for both warm days and cooler nights during your travels.

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 18°C (64°F), with highs reaching up to 30°C (87°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec636669747878777777736864
Data source: Temperature data for San Francisco generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
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 62 mm (2.4 in) over the course of 9 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 62 mm (2.4 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec927911211718521114119121228712762
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

December Humidity in San Francisco

In San Francisco in December humidity is 91%. With an average temperature of 18°C (64°F), this humidity feels like a thick blanket enveloping you, making any outdoor activities somewhat draining and requiring frequent hydration to stay comfortable while exploring.

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 91%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%86%83%80%82%79%72%74%84%92%91%91%
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.
JanFebMarAprMayJunJulAugSepOctNovDec811121313131313131197
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 Weather17°C (63°F)92 mm (3.6 inches)88%very high
February Weather19°C (66°F)79 mm (3.1 inches)86%extreme
March Weather21°C (70°F)112 mm (4.4 inches)83%extreme
April Weather23°C (74°F)117 mm (4.6 inches)80%extreme
May Weather25°C (78°F)185 mm (7.3 inches)82%extreme
June Weather25°C (78°F)210 mm (8.3 inches)79%extreme
July Weather25°C (77°F)141 mm (5.5 inches)72%extreme
August Weather25°C (78°F)191 mm (7.5 inches)74%extreme
September Weather25°C (77°F)212 mm (8.4 inches)84%extreme
October Weather23°C (74°F)287 mm (11.3 inches)92%extreme
November Weather20°C (68°F)127 mm (5.0 inches)91%very high
December Weather18°C (64°F)62 mm (2.4 inches)91%high

Compare San Francisco's Climate with Cities Worldwide