December Weather in Fountain Valley, United States

Last updated: June 24, 2025

In December, the average temperature in Fountain Valley, United States is a mild 14°C (58°F), with minimums dropping to 5°C (42°F) and maximums reaching up to 27°C (82°F). Expect about 68 mm (2.7 in) of precipitation over 5 days, accompanied by an average humidity of 71%. Perfect for enjoying the unique charm of the season!

December Temperature in Fountain Valley

In December in Fountain Valley, the average temperature is 14°C (58°F). The maximum can reach 27°C (82°F), and the minimum can be as low as 5°C (42°F). This moderate climate makes Fountain Valley an ideal destination for travelers seeking comfortable weather and a pleasant atmosphere.

December Weather in Fountain Valley: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Fountain Valley, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fountain Valley, December typically has an average temperature of 14°C (58°F), with highs reaching up to 27°C (82°F) and lows dropping to around 5°C (42°F).

Data source: Temperature data for Fountain Valley generated using information from the Copernicus Climate Change Service.

December Precipitation in Fountain Valley

In Fountain Valley in December, the total precipitation amount is 68 mm (2.7 in) over the course of 5 days.

December Precipitation Trends in Fountain Valley

The chart displays monthly precipitation patterns in Fountain Valley, 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 Fountain Valley, December typically receives around 68 mm (2.7 inches) of precipitation spread over approximately 5 days.

Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

December Humidity in Fountain Valley

In Fountain Valley in December humidity is 71%. With an average temperature of 14°C (58°F), this humidity feels like a damp embrace, making it essential for travelers to pack light, breathable clothing and stay hydrated while exploring the sights.

December Average Humidity in Fountain Valley

This chart illustrates the average monthly humidity levels in Fountain Valley, 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 Fountain Valley is approximately 71%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Fountain Valley

In Fountain Valley 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 Fountain Valley for better planning.

Maximum UV Index Levels in Fountain Valley for December

The chart shows the monthly maximum UV Index (UVI) for Fountain Valley 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 Fountain Valley typically reaches 4, which falls under the moderate exposure category.

Data source: Fountain Valley 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 Fountain Valley Compares to Other Months

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

This table compares monthly weather conditions in Fountain Valley, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	14°C (57°F)	65 mm (2.5 inches)	74%	moderate
February Weather	14°C (58°F)	52 mm (2.0 inches)	79%	high
March Weather	15°C (60°F)	55 mm (2.2 inches)	75%	very high
April Weather	17°C (63°F)	23 mm (0.9 inches)	70%	very high
May Weather	18°C (64°F)	12 mm (0.5 inches)	70%	very high
June Weather	20°C (68°F)	4 mm (0.2 inches)	72%	extreme
July Weather	22°C (72°F)	3 mm (0.1 inches)	73%	extreme
August Weather	23°C (73°F)	2 mm (0.1 inches)	69%	very high
September Weather	22°C (72°F)	3 mm (0.1 inches)	68%	very high
October Weather	20°C (69°F)	9 mm (0.4 inches)	67%	high
November Weather	17°C (63°F)	18 mm (0.7 inches)	68%	moderate
December Weather	14°C (58°F)	68 mm (2.7 inches)	71%	moderate