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December Weather in Eureka, United States

Last updated: June 24, 2025

In Eureka, United States, the average temperature in December hovers around -3°C (28°F). Temperatures can dip as low as -18°C (0°F), while the highs can reach up to 15°C (59°F). This month typically sees 42 mm (1.6 in) of precipitation over 8 days, with an average humidity of 87%, making it a chilly, damp time of year.

December Temperature in Eureka

In December in Eureka, the average temperature is -3°C (28°F), with maximums reaching 15°C (59°F) and minimums dropping as low as -18°C (0°F). Travelers should be prepared for a wide range of temperatures and dress accordingly to enjoy their visit.

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

The chart illustrates December temperature patterns in Eureka, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Eureka, December typically has an average temperature of -3°C (28°F), with highs reaching up to 15°C (59°F) and lows dropping to around -18°C (0°F).
JanFebMarAprMayJunJulAugSepOctNovDec253039496074827969514127
Data source: Temperature data for Eureka 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 Eureka

In Eureka in December, the precipitation amount is 42 mm (1.6 in) over a span of 8 days.

December Precipitation Trends in Eureka

The chart displays monthly precipitation patterns in Eureka, 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 Eureka, December typically receives around 42 mm (1.6 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec45486047421092021352742
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Eureka

In Eureka in December humidity is 87%. With an average temperature of -3°C (28°F), this humidity feels like a biting chill that clings to your skin, making travel quite uncomfortable and forcing you to bundle up extra just to stay warm.

December Average Humidity in Eureka

This chart illustrates the average monthly humidity levels in Eureka, 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 Eureka is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%77%70%54%45%37%34%47%67%82%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Eureka

In Eureka 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 Eureka, you can check the information here.

Maximum UV Index Levels in Eureka for December

The chart shows the monthly maximum UV Index (UVI) for Eureka 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 Eureka typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46710111212119753
Data source: Eureka 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 Eureka Compares to Other Months

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

This table compares monthly weather conditions in Eureka, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)44 mm (1.8 inches)87%moderate
February Weather-1°C (30°F)48 mm (1.9 inches)88%high
March Weather4°C (39°F)60 mm (2.4 inches)77%high
April Weather10°C (50°F)47 mm (1.8 inches)69%very high
May Weather15°C (60°F)42 mm (1.6 inches)54%extreme
June Weather23°C (74°F)10 mm (0.4 inches)45%extreme
July Weather28°C (82°F)9 mm (0.3 inches)37%extreme
August Weather26°C (79°F)20 mm (0.8 inches)34%extreme
September Weather21°C (69°F)21 mm (0.8 inches)47%very high
October Weather10°C (51°F)35 mm (1.4 inches)67%high
November Weather5°C (41°F)27 mm (1.1 inches)82%moderate
December Weather-3°C (28°F)42 mm (1.6 inches)87%moderate

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