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December Weather in San Francisco, El Salvador

Last updated: August 23, 2025

In December, the average temperature in San Francisco, El Salvador is a pleasant 25°C (77°F). Expect minimums dipping to 16°C (61°F) and maximums soaring up to 35°C (95°F). With just 4 mm (0.2 in) of precipitation on 0 days, you'll enjoy generally dry conditions. The atmosphere is moderately humid, with an average humidity of 66%, creating a comfortable environment throughout the month.

December Temperature in San Francisco

In December in San Francisco, the average temperature is 25°C (77°F). The maximum can reach 35°C (95°F), while the minimum can drop as low as 16°C (61°F). This makes it an ideal time for travelers seeking warm weather and comfortable conditions for outdoor activities.

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 35°C (95°F) and lows dropping to around 16°C (61°F).
JanFebMarAprMayJunJulAugSepOctNovDec788082828079818078777777
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 4 mm (0.2 in) over the course of 0 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 4 mm (0.2 inches) of precipitation spread over approximately 0 days.
JanFebMarAprMayJunJulAugSepOctNovDec2265533226797234295335644
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 66%. With an average temperature of 25°C (77°F), this humidity feels like a warm embrace, making travel a pleasant experience as the air is saturated but still breathable, allowing for comfortable exploration.

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 66%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec63%62%59%59%59%68%78%79%77%77%75%67%
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.
JanFebMarAprMayJunJulAugSepOctNovDec11121414141413131313109
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 Weather26°C (78°F)2 mm (0.1 inches)63%extreme
February Weather27°C (80°F)2 mm (0.1 inches)62%extreme
March Weather28°C (83°F)6 mm (0.2 inches)59%extreme
April Weather28°C (83°F)55 mm (2.2 inches)59%extreme
May Weather27°C (80°F)332 mm (13.1 inches)59%extreme
June Weather26°C (79°F)267 mm (10.5 inches)68%extreme
July Weather27°C (81°F)97 mm (3.8 inches)77%extreme
August Weather26°C (80°F)234 mm (9.2 inches)79%extreme
September Weather26°C (78°F)295 mm (11.6 inches)77%extreme
October Weather25°C (77°F)335 mm (13.2 inches)77%extreme
November Weather25°C (77°F)64 mm (2.5 inches)75%very high
December Weather25°C (77°F)4 mm (0.2 inches)66%very high

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