December Weather in Upland, United States

Last updated: June 24, 2025

In Upland, United States, the average temperature in December hovers around 2°C (35°F), with extremes ranging from a chilling -23°C (-8°F) to a milder 17°C (63°F). Expect 68 mm (2.7 in) of precipitation spread over about 10 days, complemented by a high average humidity of 86%. Prepare for a winter experience that is both cold and damp!

December Temperature in Upland

In December in Upland, the average temperature is 2°C (35°F). The maximum can reach 17°C (63°F) and the minimum can be as low as -23°C (-8°F). Be prepared for a wide range of temperatures, making this an ideal time for travelers who enjoy cool weather and winter activities.

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

The chart illustrates December temperature patterns in Upland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Upland, December typically has an average temperature of 2°C (35°F), with highs reaching up to 17°C (63°F) and lows dropping to around -23°C (-8°F).

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

December Precipitation in Upland

In Upland in December, the precipitation amount is 68 mm (2.7 in) over a span of 10 days.

December Precipitation Trends in Upland

The chart displays monthly precipitation patterns in Upland, 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 Upland, December typically receives around 68 mm (2.7 inches) of precipitation spread over approximately 10 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

December Humidity in Upland

In Upland in December humidity is 86%. With an average temperature of 2°C (35°F), this humidity feels like a damp chill that seeps into your bones, making traveling quite uncomfortable as your clothes cling to you and the cold air cuts through any warmth you try to find.

December Average Humidity in Upland

This chart illustrates the average monthly humidity levels in Upland, 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 Upland is approximately 86%, 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 Upland

In Upland 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 Upland, you can visit Hourly UV Index in Upland.

Maximum UV Index Levels in Upland for December

The chart shows the monthly maximum UV Index (UVI) for Upland 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 Upland typically reaches 2, which falls under the low exposure category.

Data source: Upland 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 Upland Compares to Other Months

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

This table compares monthly weather conditions in Upland, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (29°F)	76 mm (3.0 inches)	85%	moderate
February Weather	0°C (32°F)	86 mm (3.4 inches)	85%	moderate
March Weather	5°C (42°F)	104 mm (4.1 inches)	86%	high
April Weather	10°C (51°F)	94 mm (3.7 inches)	87%	very high
May Weather	17°C (63°F)	133 mm (5.3 inches)	81%	very high
June Weather	23°C (73°F)	106 mm (4.2 inches)	82%	extreme
July Weather	24°C (76°F)	106 mm (4.2 inches)	81%	very high
August Weather	23°C (73°F)	100 mm (3.9 inches)	79%	very high
September Weather	20°C (69°F)	71 mm (2.8 inches)	78%	very high
October Weather	14°C (57°F)	101 mm (4.0 inches)	81%	high
November Weather	5°C (41°F)	83 mm (3.3 inches)	89%	moderate
December Weather	2°C (35°F)	68 mm (2.7 inches)	86%	low