nomadseason

December Weather in Fontana, United States

Last updated: June 24, 2025

In December, the average temperature in Fontana, United States hovers around -1°C (31°F), with extremes ranging from a brisk -22°C (-7°F) to a mild 19°C (66°F). Expect about 52 mm (2.1 in) of precipitation over 7 days, coupled with an average humidity of 81%.

December Temperature in Fontana

In December in Fontana, the average temperature is -1°C (31°F), with a maximum reaching 19°C (66°F) and a minimum plummeting to -22°C (-7°F). Travelers should be prepared for a wide range of temperatures, ensuring they pack appropriately for both warmth and cooler conditions.

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

The chart illustrates December temperature patterns in Fontana, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fontana, December typically has an average temperature of -1°C (31°F), with highs reaching up to 19°C (66°F) and lows dropping to around -22°C (-7°F).
JanFebMarAprMayJunJulAugSepOctNovDec232537465970757266523731
Data source: Temperature data for Fontana 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 Fontana

In Fontana in December, the precipitation amount is 52 mm (2.1 in) over the course of 7 days.

December Precipitation Trends in Fontana

The chart displays monthly precipitation patterns in Fontana, 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 Fontana, December typically receives around 52 mm (2.1 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec61586611015411584911041194952
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

December Humidity in Fontana

In Fontana in December humidity is 81%. With an average temperature of -1°C (31°F), this humidity feels like a heavy, cold mist that clings to your skin, making outdoor adventures damp and challenging.

December Average Humidity in Fontana

This chart illustrates the average monthly humidity levels in Fontana, 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 Fontana is approximately 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Fontana

In Fontana in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Fontana, you can visit Hourly UV Index in Fontana.

Maximum UV Index Levels in Fontana for December

The chart shows the monthly maximum UV Index (UVI) for Fontana 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 Fontana typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098532
Data source: Fontana 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 Fontana Compares to Other Months

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

This table compares monthly weather conditions in Fontana, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-5°C (23°F)61 mm (2.4 inches)85%moderate
February Weather-4°C (25°F)58 mm (2.3 inches)85%moderate
March Weather3°C (37°F)66 mm (2.6 inches)85%high
April Weather8°C (47°F)110 mm (4.3 inches)85%very high
May Weather15°C (60°F)154 mm (6.0 inches)78%very high
June Weather21°C (71°F)115 mm (4.5 inches)80%very high
July Weather24°C (75°F)84 mm (3.3 inches)78%very high
August Weather22°C (72°F)91 mm (3.6 inches)76%very high
September Weather19°C (66°F)104 mm (4.1 inches)79%very high
October Weather11°C (53°F)119 mm (4.7 inches)83%moderate
November Weather3°C (37°F)49 mm (1.9 inches)88%moderate
December Weather-1°C (31°F)52 mm (2.1 inches)81%low

Compare Fontana's Climate with Cities Worldwide