December Weather in Lewistown, United States

Last updated: June 24, 2025

In December, the average temperature in Lewistown, United States hovers around 1°C (35°F). You may experience a chilly minimum of -21°C (-5°F), while the mercury can rise to a pleasant 21°C (71°F). Expect about 52 mm (2.0 in) of precipitation spread over 6 days, and keep in mind the average humidity is a humid 84%.

December Temperature in Lewistown

In December in Lewistown, the average temperature is 1°C (35°F). Maximums can reach 21°C (71°F) and minimums can be as low as -21°C (-5°F). Be prepared for a wide range of temperatures, making it essential to pack accordingly for your travels.

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

The chart illustrates December temperature patterns in Lewistown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lewistown, December typically has an average temperature of 1°C (35°F), with highs reaching up to 21°C (71°F) and lows dropping to around -21°C (-5°F).

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

December Precipitation in Lewistown

In Lewistown, in December, the precipitation amount is 52 mm (2.0 in) over the course of 6 days.

December Precipitation Trends in Lewistown

The chart displays monthly precipitation patterns in Lewistown, 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 Lewistown, December typically receives around 52 mm (2.0 inches) of precipitation spread over approximately 6 days.

Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

December Humidity in Lewistown

In Lewistown in December humidity is 84%. With an average temperature of 1°C (35°F), this humidity feels like a cold, damp chill that seeps into your bones, making it feel much colder than the thermometer suggests, which can be quite uncomfortable for traveling.

December Average Humidity in Lewistown

This chart illustrates the average monthly humidity levels in Lewistown, 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 Lewistown is approximately 84%, 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 Lewistown

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

Maximum UV Index Levels in Lewistown for December

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

Data source: Lewistown 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 Lewistown Compares to Other Months

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

This table compares monthly weather conditions in Lewistown, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-3°C (27°F)	60 mm (2.4 inches)	81%	moderate
February Weather	-1°C (30°F)	68 mm (2.7 inches)	81%	moderate
March Weather	6°C (42°F)	121 mm (4.8 inches)	81%	high
April Weather	11°C (51°F)	108 mm (4.3 inches)	82%	very high
May Weather	18°C (64°F)	169 mm (6.7 inches)	78%	very high
June Weather	24°C (75°F)	152 mm (6.0 inches)	81%	extreme
July Weather	25°C (78°F)	103 mm (4.0 inches)	79%	very high
August Weather	24°C (75°F)	86 mm (3.4 inches)	77%	very high
September Weather	21°C (70°F)	74 mm (2.9 inches)	78%	very high
October Weather	13°C (56°F)	117 mm (4.6 inches)	78%	high
November Weather	5°C (41°F)	57 mm (2.2 inches)	87%	moderate
December Weather	1°C (35°F)	52 mm (2.0 inches)	84%	low