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December Weather in San Carlos, United States

Last updated: June 24, 2025

In December, the average temperature in San Carlos, United States hovers around 13°C (55°F), with a minimum dipping to 0°C (32°F) and a maximum peaking at 28°C (83°F). Expect around 26 mm (1.0 in) of precipitation over 4 days, accompanied by a relatively high average humidity of 82%.

December Temperature in San Carlos

In December in San Carlos, the average temperature is 13°C (55°F). The maximum can reach 28°C (83°F), while the minimum can drop as low as 0°C (32°F). This range of temperatures makes it advisable for travelers to pack layers to comfortably enjoy both warm and cooler moments during their visit.

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

The chart illustrates December temperature patterns in San Carlos, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Carlos, December typically has an average temperature of 13°C (55°F), with highs reaching up to 28°C (83°F) and lows dropping to around 0°C (32°F).
JanFebMarAprMayJunJulAugSepOctNovDec545764748192949488756555
Data source: Temperature data for San Carlos 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 Carlos

In San Carlos in December, the precipitation amount is 26 mm (1.0 in) over the course of 4 days.

December Precipitation Trends in San Carlos

The chart displays monthly precipitation patterns in San Carlos, 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 Carlos, December typically receives around 26 mm (1.0 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec243623223373524211926
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in San Carlos

In San Carlos in December, humidity is 82%. With an average temperature of 13°C (55°F), this humidity feels like a heavy blanket wrapping around you, making outdoor activities sticky and uncomfortable for traveling.

December Average Humidity in San Carlos

This chart illustrates the average monthly humidity levels in San Carlos, 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 Carlos is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%79%67%55%40%33%34%48%64%67%77%82%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in San Carlos

In San Carlos in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in San Carlos for better planning.

Maximum UV Index Levels in San Carlos for December

The chart shows the monthly maximum UV Index (UVI) for San Carlos 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 Carlos typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec469111112111110854
Data source: San Carlos 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 Carlos Compares to Other Months

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

This table compares monthly weather conditions in San Carlos, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather12°C (54°F)24 mm (0.9 inches)76%moderate
February Weather14°C (57°F)36 mm (1.4 inches)79%high
March Weather18°C (65°F)23 mm (0.9 inches)67%very high
April Weather24°C (75°F)2 mm (0.1 inches)55%extreme
May Weather27°C (82°F)2 mm (0.1 inches)40%extreme
June Weather33°C (92°F)3 mm (0.1 inches)33%extreme
July Weather35°C (95°F)37 mm (1.5 inches)34%extreme
August Weather34°C (94°F)35 mm (1.4 inches)48%extreme
September Weather31°C (88°F)24 mm (0.9 inches)64%very high
October Weather24°C (76°F)21 mm (0.8 inches)67%very high
November Weather19°C (66°F)19 mm (0.7 inches)77%moderate
December Weather13°C (55°F)26 mm (1.0 inches)82%moderate

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