nomadseason

December Weather in Rancho Cucamonga, United States

Last updated: June 24, 2025

In Rancho Cucamonga, United States, the average temperature in December is 12°C (54°F), with daily highs reaching up to 29°C (84°F) and lows dipping to 0°C (32°F). Expect a total precipitation of 87 mm (3.4 in) spread across about 6 days, contributing to an average humidity of 71%. This creates a unique climate that combines cool breezes with enticing moisture.

December Temperature in Rancho Cucamonga

In December in Rancho Cucamonga, the average temperature is 12°C (54°F). Maximum can reach 29°C (84°F) and minimum can be as low as 0°C (32°F). This makes Rancho Cucamonga a versatile destination for travelers, perfect for enjoying both warm days and cooler nights.

December Weather in Rancho Cucamonga: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Rancho Cucamonga, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rancho Cucamonga, December typically has an average temperature of 12°C (54°F), with highs reaching up to 29°C (84°F) and lows dropping to around 0°C (32°F).
JanFebMarAprMayJunJulAugSepOctNovDec535456636573798076696153
Data source: Temperature data for Rancho Cucamonga generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Rancho Cucamonga

In Rancho Cucamonga in December, the precipitation amount is 87 mm (3.4 in) spread over a period of 6 days.

December Precipitation Trends in Rancho Cucamonga

The chart displays monthly precipitation patterns in Rancho Cucamonga, 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 Rancho Cucamonga, December typically receives around 87 mm (3.4 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec87849535233126153588
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

December Humidity in Rancho Cucamonga

In Rancho Cucamonga in December humidity is 71%. With an average temperature of 12°C (54°F), this humidity feels like a damp chill that clings to your skin, making it essential to dress in layers while exploring the area, as the cool air can be refreshing yet slightly uncomfortable without proper attire for outdoor activities.

December Average Humidity in Rancho Cucamonga

This chart illustrates the average monthly humidity levels in Rancho Cucamonga, 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 Rancho Cucamonga is approximately 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec74%79%75%71%70%72%73%69%68%67%68%71%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Rancho Cucamonga

In Rancho Cucamonga 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 Rancho Cucamonga for better planning.

Maximum UV Index Levels in Rancho Cucamonga for December

The chart shows the monthly maximum UV Index (UVI) for Rancho Cucamonga 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 Rancho Cucamonga typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101012111010754
Data source: Rancho Cucamonga 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 Rancho Cucamonga Compares to Other Months

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

This table compares monthly weather conditions in Rancho Cucamonga, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather12°C (54°F)87 mm (3.4 inches)74%moderate
February Weather12°C (54°F)84 mm (3.3 inches)79%high
March Weather14°C (57°F)95 mm (3.7 inches)75%very high
April Weather17°C (63°F)35 mm (1.4 inches)70%very high
May Weather18°C (66°F)23 mm (0.9 inches)70%very high
June Weather23°C (73°F)3 mm (0.1 inches)72%extreme
July Weather26°C (80°F)1 mm (0.1 inches)73%extreme
August Weather26°C (80°F)2 mm (0.1 inches)69%very high
September Weather24°C (76°F)5 mm (0.2 inches)68%very high
October Weather20°C (69°F)15 mm (0.6 inches)67%high
November Weather16°C (61°F)35 mm (1.4 inches)68%moderate
December Weather12°C (54°F)87 mm (3.4 inches)71%moderate

Compare Rancho Cucamonga's Climate with Cities Worldwide