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December Weather in Hillsborough, United States

Last updated: June 24, 2025

In December, the average temperature in Hillsborough, United States hovers around -2°C (28°F), with extremes ranging from a chilly -22°C (-8°F) to a milder 16°C (61°F). Expect about 120 mm (4.7 in) of precipitation over approximately 9 days, and be prepared for a notably high average humidity of 81%.

December Temperature in Hillsborough

In December in Hillsborough, the average temperature is -2°C (28°F), with maximums reaching 16°C (61°F) and minimums dropping as low as -22°C (-8°F). Travelers should be prepared for a wide range of temperatures and pack accordingly.

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 -2°C (28°F), with highs reaching up to 16°C (61°F) and lows dropping to around -22°C (-8°F).
JanFebMarAprMayJunJulAugSepOctNovDec242733455667727063513728
Data source: Temperature data for Hillsborough generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Hillsborough

In Hillsborough in December, the precipitation amount is 120 mm (4.7 in) over the course 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 120 mm (4.7 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec748881130868914010187135104120
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Hillsborough

In Hillsborough in December, humidity is 81%. With an average temperature of -2°C (28°F), this humidity feels like a biting chill that seeps into your bones, making travel uncomfortable and necessitating extra layers to stay warm and dry.

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 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
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 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 Hillsborough, you can visit Hourly UV Index in Hillsborough.

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 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3468910997632
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.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (24°F)74 mm (2.9 inches)86%moderate
February Weather-3°C (27°F)88 mm (3.5 inches)84%moderate
March Weather0°C (33°F)81 mm (3.2 inches)82%high
April Weather7°C (45°F)130 mm (5.1 inches)80%very high
May Weather14°C (57°F)86 mm (3.4 inches)72%very high
June Weather19°C (67°F)89 mm (3.5 inches)72%very high
July Weather22°C (72°F)140 mm (5.5 inches)67%very high
August Weather21°C (70°F)101 mm (4.0 inches)66%very high
September Weather17°C (63°F)87 mm (3.4 inches)71%high
October Weather11°C (52°F)135 mm (5.3 inches)78%high
November Weather3°C (37°F)104 mm (4.1 inches)84%moderate
December Weather-2°C (28°F)120 mm (4.7 inches)81%low

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