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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 1°C (35°F), with extremes ranging from a chilly -21°C (-6°F) to a pleasant 24°C (76°F). Expect 18 mm (0.7 in) of precipitation spread across 3 days, and enjoy the crisp air with an average humidity of 77%.

December Temperature in Harrisburg

In December in Harrisburg, the average temperature is 1°C (35°F). The maximum can reach 24°C (76°F), while the minimum can drop as low as -21°C (-6°F). Be sure to pack layers and prepare for a wide range of temperatures during your travels!

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 1°C (35°F), with highs reaching up to 24°C (76°F) and lows dropping to around -21°C (-6°F).
JanFebMarAprMayJunJulAugSepOctNovDec322940465569757266484134
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 18 mm (0.7 in) over a span of 3 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 18 mm (0.7 inches) of precipitation spread over approximately 3 days.
JanFebMarAprMayJunJulAugSepOctNovDec1423685311757473524362518
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 77%. With an average temperature of 1°C (35°F), this humidity feels like a heavy fog, making travel feel damp and chilly, as the cold air clings to your skin and every breath is filled with moisture.

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 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec72%76%62%60%74%82%82%84%75%73%74%77%
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.
JanFebMarAprMayJunJulAugSepOctNovDec3579101111109643
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 Weather0°C (32°F)14 mm (0.6 inches)72%moderate
February Weather-2°C (30°F)23 mm (0.9 inches)76%moderate
March Weather5°C (40°F)67 mm (2.7 inches)61%high
April Weather8°C (46°F)53 mm (2.1 inches)60%very high
May Weather13°C (55°F)117 mm (4.6 inches)74%very high
June Weather21°C (69°F)57 mm (2.2 inches)82%extreme
July Weather24°C (75°F)46 mm (1.8 inches)82%extreme
August Weather22°C (73°F)35 mm (1.4 inches)84%very high
September Weather19°C (66°F)24 mm (1.0 inches)75%very high
October Weather9°C (48°F)36 mm (1.4 inches)73%high
November Weather5°C (42°F)25 mm (1.0 inches)74%moderate
December Weather1°C (35°F)18 mm (0.7 inches)77%moderate

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