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December Weather in Walnut Creek, United States

Last updated: June 24, 2025

In December, the average temperature in Walnut Creek, United States hovers around 8°C (47°F). Expect a chilly minimum of -2°C (28°F) and a comfortable maximum of 23°C (74°F). The region experiences an average precipitation of 21 mm (0.8 in) over the course of about 3 days, accompanied by a 77% average humidity, creating a fresh atmosphere throughout the month.

December Temperature in Walnut Creek

In December in Walnut Creek, the average temperature is 8°C (47°F). The maximum can reach 23°C (74°F) and the minimum can be as low as -2°C (28°F). This varied weather makes Walnut Creek an interesting destination for travelers looking to experience a range of conditions.

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

The chart illustrates December temperature patterns in Walnut Creek, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Walnut Creek, December typically has an average temperature of 8°C (47°F), with highs reaching up to 23°C (74°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec474956667385898981675747
Data source: Temperature data for Walnut 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 Walnut Creek

In Walnut Creek in December, the precipitation amount is 21 mm (0.8 in) over a period of 3 days.

December Precipitation Trends in Walnut Creek

The chart displays monthly precipitation patterns in Walnut 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 Walnut Creek, December typically receives around 21 mm (0.8 inches) of precipitation spread over approximately 3 days.
JanFebMarAprMayJunJulAugSepOctNovDec282936872331415202621
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Walnut Creek

In Walnut Creek in December, humidity is 77%. With an average temperature of 8°C (47°F), this humidity feels like a damp chill that can make even short walks outside feel uncomfortable, often clinging to your skin and making you long for warmer, drier conditions.

December Average Humidity in Walnut Creek

This chart illustrates the average monthly humidity levels in Walnut 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 Walnut Creek is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec77%80%68%58%45%31%27%30%48%60%70%77%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Walnut Creek

In Walnut Creek 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 Walnut Creek for better planning.

Maximum UV Index Levels in Walnut Creek for December

The chart shows the monthly maximum UV Index (UVI) for Walnut 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 Walnut Creek typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101112121110754
Data source: Walnut 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 Walnut Creek Compares to Other Months

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

This table compares monthly weather conditions in Walnut Creek, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather8°C (47°F)28 mm (1.1 inches)77%moderate
February Weather10°C (49°F)29 mm (1.1 inches)80%high
March Weather13°C (56°F)36 mm (1.4 inches)68%very high
April Weather19°C (67°F)8 mm (0.3 inches)58%very high
May Weather23°C (74°F)7 mm (0.3 inches)45%extreme
June Weather30°C (86°F)1 mm (0.1 inches)31%extreme
July Weather32°C (89°F)32 mm (1.3 inches)27%extreme
August Weather32°C (89°F)14 mm (0.6 inches)30%extreme
September Weather27°C (81°F)15 mm (0.6 inches)48%very high
October Weather19°C (67°F)20 mm (0.8 inches)59%high
November Weather14°C (57°F)26 mm (1.0 inches)70%moderate
December Weather8°C (47°F)21 mm (0.8 inches)77%moderate

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