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December Weather in Fairfield, United States

Last updated: June 24, 2025

The average temperature in Fairfield, United States during December is 4°C (40°F). Temperatures can vary significantly, with minimums dipping to -16°C (3°F) and maximums soaring to 21°C (70°F). Prepare for a wet month, as precipitation amounts reach 92 mm (3.6 in) over approximately 9 days. Don't forget, the average humidity is a high 87%, adding a chill to the air!

December Temperature in Fairfield

In December in Fairfield, the average temperature is 4°C (40°F). The maximum can reach 21°C (70°F) while the minimum can drop as low as -16°C (3°F). Travelers should prepare for a wide range of temperatures and pack accordingly.

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

The chart illustrates December temperature patterns in Fairfield, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fairfield, December typically has an average temperature of 4°C (40°F), with highs reaching up to 21°C (70°F) and lows dropping to around -16°C (3°F).
JanFebMarAprMayJunJulAugSepOctNovDec343747566877807773604440
Data source: Temperature data for Fairfield 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 Fairfield

In Fairfield in December, the precipitation amount is 92 mm (3.6 in) during 9 days, indicating a relatively wet period for the region.

December Precipitation Trends in Fairfield

The chart displays monthly precipitation patterns in Fairfield, 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 Fairfield, December typically receives around 92 mm (3.6 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec921061351171381148988691089992
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Fairfield

In Fairfield in December humidity is 87%. With an average temperature of 4°C (40°F), this humidity feels like an uncomfortable chill that seeps into your bones, making it essential to dress warmly and prepare for damp conditions, which can dampen your spirits while traveling.

December Average Humidity in Fairfield

This chart illustrates the average monthly humidity levels in Fairfield, 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 Fairfield is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%84%83%80%83%82%83%79%79%88%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Fairfield

In Fairfield in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Fairfield, you can check the information here.

Maximum UV Index Levels in Fairfield for December

The chart shows the monthly maximum UV Index (UVI) for Fairfield 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 Fairfield typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579111110109753
Data source: Fairfield 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 Fairfield Compares to Other Months

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

This table compares monthly weather conditions in Fairfield, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)92 mm (3.6 inches)84%moderate
February Weather3°C (37°F)106 mm (4.2 inches)82%moderate
March Weather9°C (48°F)135 mm (5.3 inches)84%high
April Weather13°C (56°F)116 mm (4.6 inches)83%very high
May Weather20°C (69°F)138 mm (5.4 inches)80%extreme
June Weather25°C (77°F)114 mm (4.5 inches)83%extreme
July Weather27°C (80°F)88 mm (3.5 inches)82%very high
August Weather25°C (77°F)88 mm (3.5 inches)82%very high
September Weather23°C (73°F)69 mm (2.7 inches)79%very high
October Weather16°C (61°F)107 mm (4.2 inches)79%high
November Weather7°C (45°F)99 mm (3.9 inches)88%moderate
December Weather4°C (40°F)92 mm (3.6 inches)87%moderate

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