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December Weather in Harrisburg, United States

Last updated: June 24, 2025

In Harrisburg, United States, the average temperature in December hovers around 8°C (47°F). Expect a varied range, with minimums plummeting to -7°C (19°F) and highs peaking at 25°C (78°F). Precipitation typically amounts to 120 mm (4.7 in) over 10 days, while the air remains quite humid, with an average humidity of 87%.

December Temperature in Harrisburg

In December in Harrisburg, the average temperature is 8°C (47°F), with maximums reaching 25°C (78°F) and minimums dipping as low as -7°C (19°F). Travelers should be prepared for a wide range of temperatures, making layering essential for comfort during their visit.

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

The chart illustrates December temperature patterns in Harrisburg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Harrisburg, December typically has an average temperature of 8°C (47°F), with highs reaching up to 25°C (78°F) and lows dropping to around -7°C (19°F).
JanFebMarAprMayJunJulAugSepOctNovDec434954627177817974655147
Data source: Temperature data for Harrisburg 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 Harrisburg

In Harrisburg in December, the precipitation amount is 120 mm (4.7 in) spread over a duration of 10 days.

December Precipitation Trends in Harrisburg

The chart displays monthly precipitation patterns in Harrisburg, 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 Harrisburg, December typically receives around 120 mm (4.7 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec9211683103113821141051339290120
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Harrisburg

In Harrisburg in December, humidity is 87%. With an average temperature of 8°C (47°F), this humidity feels like a damp chill that clings to your skin, making outdoor exploration uncomfortably muggy despite the cool air.

December Average Humidity in Harrisburg

This chart illustrates the average monthly humidity levels in Harrisburg, 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 Harrisburg is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%85%84%82%83%82%80%74%75%79%87%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Harrisburg

In Harrisburg 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 Harrisburg, you can check the information here.

Maximum UV Index Levels in Harrisburg for December

The chart shows the monthly maximum UV Index (UVI) for Harrisburg 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 Harrisburg typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46810101110109853
Data source: Harrisburg 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 Harrisburg Compares to Other Months

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

This table compares monthly weather conditions in Harrisburg, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather6°C (44°F)92 mm (3.6 inches)86%moderate
February Weather9°C (49°F)116 mm (4.6 inches)85%high
March Weather12°C (54°F)83 mm (3.3 inches)84%very high
April Weather17°C (62°F)103 mm (4.0 inches)82%very high
May Weather22°C (71°F)113 mm (4.5 inches)83%very high
June Weather25°C (77°F)82 mm (3.2 inches)82%extreme
July Weather27°C (81°F)114 mm (4.5 inches)80%very high
August Weather26°C (79°F)105 mm (4.1 inches)74%very high
September Weather23°C (75°F)133 mm (5.2 inches)75%very high
October Weather18°C (65°F)92 mm (3.6 inches)79%very high
November Weather10°C (51°F)90 mm (3.5 inches)87%moderate
December Weather8°C (47°F)120 mm (4.7 inches)87%moderate

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