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December Weather in Fallbrook, United States

Last updated: June 24, 2025

In Fallbrook, United States, the average temperature in December hovers around 13°C (55°F), with fluctuations between a refreshing 2°C (35°F) and a warm 28°C (82°F). Expect about 66 mm (2.6 in) of precipitation over 5 days, accompanied by an average humidity of 74%. Perfect for cozy activities or exploring the outdoors!

December Temperature in Fallbrook

In December in Fallbrook, the average temperature is 13°C (55°F), with maximums reaching 28°C (82°F) and minimums dropping as low as 2°C (35°F). This variability makes it a great time to explore, so be sure to pack for both warm and cool weather while you enjoy all that Fallbrook has to offer.

December Weather in Fallbrook: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Fallbrook, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fallbrook, December typically has an average temperature of 13°C (55°F), with highs reaching up to 28°C (82°F) and lows dropping to around 2°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec555557626470767774696255
Data source: Temperature data for Fallbrook 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 Fallbrook

In Fallbrook in December, the precipitation amount is 66 mm (2.6 in) over a span of 5 days.

December Precipitation Trends in Fallbrook

The chart displays monthly precipitation patterns in Fallbrook, 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 Fallbrook, December typically receives around 66 mm (2.6 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec66646731193434112866
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Fallbrook

In Fallbrook in December, humidity is 74%. With an average temperature of 13°C (55°F), this humidity feels like a damp blanket wrapping around you, making outdoor activities somewhat uncomfortable and demanding frequent breaks in shaded areas.

December Average Humidity in Fallbrook

This chart illustrates the average monthly humidity levels in Fallbrook, 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 Fallbrook is approximately 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec72%77%67%56%46%48%46%42%52%58%66%74%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Fallbrook

In Fallbrook 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 Fallbrook for better planning.

Maximum UV Index Levels in Fallbrook for December

The chart shows the monthly maximum UV Index (UVI) for Fallbrook 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 Fallbrook typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec469101112121110754
Data source: Fallbrook 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 Fallbrook Compares to Other Months

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

This table compares monthly weather conditions in Fallbrook, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather13°C (55°F)66 mm (2.6 inches)72%moderate
February Weather13°C (55°F)64 mm (2.5 inches)77%high
March Weather14°C (57°F)67 mm (2.6 inches)67%very high
April Weather17°C (62°F)31 mm (1.2 inches)56%very high
May Weather18°C (64°F)19 mm (0.8 inches)46%extreme
June Weather21°C (70°F)3 mm (0.1 inches)48%extreme
July Weather25°C (77°F)4 mm (0.2 inches)46%extreme
August Weather25°C (77°F)3 mm (0.1 inches)42%extreme
September Weather24°C (75°F)4 mm (0.2 inches)52%very high
October Weather20°C (69°F)11 mm (0.4 inches)58%high
November Weather17°C (62°F)28 mm (1.1 inches)66%moderate
December Weather13°C (55°F)66 mm (2.6 inches)74%moderate

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