December Weather in Williamsport, United States

Last updated: June 24, 2025

In Williamsport, United States during the month of December, the average temperature hovers around 2°C (36°F). Expect to experience a minimum plunge to -25°C (-14°F) and a maximum rise to 18°C (64°F). This month sees about 61 mm (2.4 in) of precipitation spread over 9 days, and you'll likely find the air quite humid, with an average humidity of 86%.

December Temperature in Williamsport

In December in Williamsport, the average temperature is 2°C (36°F). Maximums can reach 18°C (64°F), while minimums can drop as low as -25°C (-14°F). Be prepared for a wide range of temperatures, making it essential to pack layers for your travels.

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

The chart illustrates December temperature patterns in Williamsport, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Williamsport, December typically has an average temperature of 2°C (36°F), with highs reaching up to 18°C (64°F) and lows dropping to around -25°C (-14°F).

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

December Precipitation in Williamsport

In Williamsport in December, the precipitation amount is 61 mm (2.4 in) spread over 9 days.

December Precipitation Trends in Williamsport

The chart displays monthly precipitation patterns in Williamsport, 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 Williamsport, December typically receives around 61 mm (2.4 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 Williamsport

In Williamsport in December, humidity is 86%. With an average temperature of 2°C (36°F), this humidity feels like a biting chill that clings to your skin, making outdoor exploration uncomfortable and dampening any enthusiasm for travel.

December Average Humidity in Williamsport

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

In Williamsport 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 Williamsport, you can visit Hourly UV Index in Williamsport.

Maximum UV Index Levels in Williamsport for December

The chart shows the monthly maximum UV Index (UVI) for Williamsport 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 Williamsport typically reaches 2, which falls under the low exposure category.

Data source: Williamsport 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 Williamsport Compares to Other Months

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

This table compares monthly weather conditions in Williamsport, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (29°F)	76 mm (3.0 inches)	85%	moderate
February Weather	0°C (32°F)	77 mm (3.1 inches)	85%	moderate
March Weather	6°C (42°F)	112 mm (4.4 inches)	86%	high
April Weather	11°C (52°F)	104 mm (4.1 inches)	87%	very high
May Weather	18°C (64°F)	151 mm (5.9 inches)	81%	very high
June Weather	23°C (74°F)	103 mm (4.0 inches)	82%	extreme
July Weather	25°C (77°F)	93 mm (3.7 inches)	81%	very high
August Weather	23°C (74°F)	106 mm (4.2 inches)	79%	very high
September Weather	21°C (70°F)	67 mm (2.6 inches)	78%	very high
October Weather	14°C (58°F)	116 mm (4.6 inches)	81%	high
November Weather	5°C (42°F)	76 mm (3.0 inches)	89%	moderate
December Weather	2°C (36°F)	61 mm (2.4 inches)	86%	low