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December Weather in Mill Creek, United States

Last updated: June 24, 2025

In December, the average temperature in Mill Creek, United States hovers around 2°C (36°F), with fluctuations ranging from a brisk -17°C (1°F) to a mild 19°C (66°F). You can expect 129 mm (5.1 in) of precipitation over about 15 days, contributing to a notably high average humidity of 86%. Prepare for a chilly and damp experience!

December Temperature in Mill Creek

In December in Mill Creek, the average temperature is 2°C (36°F). The maximum can reach 19°C (66°F), while the minimum can drop as low as -17°C (1°F). Be prepared for a wide range of temperatures when traveling, as you may experience both chilly and milder conditions.

December Weather in Mill Creek: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Mill Creek, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mill Creek, December typically has an average temperature of 2°C (36°F), with highs reaching up to 19°C (66°F) and lows dropping to around -17°C (1°F).
JanFebMarAprMayJunJulAugSepOctNovDec303641506066706864554036
Data source: Temperature data for Mill Creek 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 Mill Creek

In Mill Creek in December, the precipitation amount is 129 mm (5.1 in) over a span of 15 days.

December Precipitation Trends in Mill Creek

The chart displays monthly precipitation patterns in Mill Creek, 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 Mill Creek, December typically receives around 129 mm (5.1 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec10515812716017414112014411612991129
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Mill Creek

In Mill Creek in December, humidity is 86%. With an average temperature of 2°C (36°F), this humidity feels like a biting chill that clings to your skin, making outdoor exploration uncomfortable and dampening any enthusiasm for travel.

December Average Humidity in Mill Creek

This chart illustrates the average monthly humidity levels in Mill Creek, 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 Mill Creek is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%88%87%82%84%82%73%74%81%89%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Mill Creek

In Mill Creek 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 Mill Creek, you can check the information here.

Maximum UV Index Levels in Mill Creek for December

The chart shows the monthly maximum UV Index (UVI) for Mill Creek 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 Mill Creek typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35710111111109753
Data source: Mill Creek 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 Mill Creek Compares to Other Months

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

This table compares monthly weather conditions in Mill Creek, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (31°F)104 mm (4.1 inches)88%moderate
February Weather2°C (36°F)158 mm (6.2 inches)88%moderate
March Weather5°C (41°F)127 mm (5.0 inches)88%high
April Weather10°C (50°F)160 mm (6.3 inches)86%very high
May Weather15°C (60°F)174 mm (6.9 inches)82%extreme
June Weather19°C (66°F)141 mm (5.6 inches)84%extreme
July Weather21°C (70°F)120 mm (4.7 inches)82%extreme
August Weather20°C (68°F)144 mm (5.7 inches)73%very high
September Weather18°C (64°F)116 mm (4.6 inches)73%very high
October Weather13°C (55°F)129 mm (5.1 inches)81%high
November Weather5°C (41°F)91 mm (3.6 inches)89%moderate
December Weather2°C (36°F)129 mm (5.1 inches)86%moderate

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