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December Weather in Harrisburg, United States

Last updated: June 24, 2025

In Harrisburg, United States, the average temperature in December is a crisp 5°C (42°F). Expect a range from a chilly -15°C (6°F) to a warm 23°C (73°F), making layering essential for your outings. With 88 mm (3.5 in) of precipitation spread over 8 days, be prepared for some rain. You'll also experience high humidity levels at 88%, so don’t forget your umbrella!

December Temperature in Harrisburg

In December in Harrisburg, the average temperature is 5°C (42°F), with a maximum that can reach 23°C (73°F) and a minimum that can dip as low as -15°C (6°F). Be prepared for a wide range of temperatures during your travels, so pack accordingly!

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 5°C (42°F), with highs reaching up to 23°C (73°F) and lows dropping to around -15°C (6°F).
JanFebMarAprMayJunJulAugSepOctNovDec363949576977807773614641
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 88 mm (3.5 in) over the course of 8 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 88 mm (3.5 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec961151371351281209184791149088
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 88%. With an average temperature of 5°C (42°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities less appealing and leading you to seek warmth indoors instead.

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 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%84%80%82%83%80%76%75%75%85%88%
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.
JanFebMarAprMayJunJulAugSepOctNovDec36710111110109753
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 Weather2°C (36°F)96 mm (3.8 inches)86%moderate
February Weather4°C (39°F)115 mm (4.5 inches)84%high
March Weather9°C (49°F)137 mm (5.4 inches)84%high
April Weather14°C (57°F)134 mm (5.3 inches)80%very high
May Weather20°C (69°F)128 mm (5.0 inches)82%extreme
June Weather25°C (77°F)120 mm (4.7 inches)83%extreme
July Weather27°C (80°F)91 mm (3.6 inches)79%very high
August Weather25°C (78°F)84 mm (3.3 inches)76%very high
September Weather23°C (74°F)79 mm (3.1 inches)75%very high
October Weather16°C (61°F)114 mm (4.5 inches)74%high
November Weather8°C (46°F)90 mm (3.5 inches)85%moderate
December Weather5°C (42°F)88 mm (3.5 inches)88%moderate

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