December Weather in Hillsborough, United States

Last updated: June 24, 2025

In December, the average temperature in Hillsborough, United States is a brisk 8°C (46°F), with temperatures ranging from a chilly -7°C (19°F) to a pleasant 23°C (73°F). Expect about 107 mm (4.2 in) of precipitation spread across 9 days, contributing to an average humidity of 86%.

December Temperature in Hillsborough

In December in Hillsborough, the average temperature is 8°C (46°F), with maximums reaching 23°C (73°F) and minimums dipping as low as -7°C (19°F). Travelers should be prepared for a wide range of temperatures, so packing layers is essential for a comfortable visit.

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

The chart illustrates December temperature patterns in Hillsborough, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hillsborough, December typically has an average temperature of 8°C (46°F), with highs reaching up to 23°C (73°F) and lows dropping to around -7°C (19°F).

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

December Precipitation in Hillsborough

In Hillsborough in December, the precipitation amount is 107 mm (4.2 in), occurring over a span of 9 days.

December Precipitation Trends in Hillsborough

The chart displays monthly precipitation patterns in Hillsborough, 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 Hillsborough, December typically receives around 107 mm (4.2 inches) of precipitation spread over approximately 9 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 Hillsborough

In Hillsborough in December humidity is 86%. With an average temperature of 8°C (46°F), this humidity feels like a damp chill enveloping you, making outdoor activities less enjoyable and requiring extra layers to stay comfortable while exploring.

December Average Humidity in Hillsborough

This chart illustrates the average monthly humidity levels in Hillsborough, 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 Hillsborough 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 Hillsborough

In Hillsborough in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Hillsborough, you can check the information here.

Maximum UV Index Levels in Hillsborough for December

The chart shows the monthly maximum UV Index (UVI) for Hillsborough 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 Hillsborough typically reaches 3, which falls under the moderate exposure category.

Data source: Hillsborough 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 Hillsborough Compares to Other Months

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

This table compares monthly weather conditions in Hillsborough, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	6°C (43°F)	89 mm (3.5 inches)	85%	moderate
February Weather	9°C (48°F)	117 mm (4.6 inches)	82%	high
March Weather	11°C (53°F)	84 mm (3.3 inches)	81%	very high
April Weather	16°C (62°F)	116 mm (4.6 inches)	80%	very high
May Weather	21°C (70°F)	118 mm (4.6 inches)	81%	extreme
June Weather	24°C (76°F)	121 mm (4.8 inches)	81%	extreme
July Weather	27°C (80°F)	114 mm (4.5 inches)	81%	extreme
August Weather	26°C (78°F)	128 mm (5.1 inches)	80%	very high
September Weather	23°C (74°F)	128 mm (5.1 inches)	79%	very high
October Weather	18°C (65°F)	97 mm (3.8 inches)	80%	very high
November Weather	10°C (51°F)	81 mm (3.2 inches)	85%	moderate
December Weather	8°C (46°F)	107 mm (4.2 inches)	86%	moderate