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December Weather in Lewistown, United States

Last updated: June 24, 2025

In December, the average temperature in Lewistown, United States hovers around 2°C (36°F). Expect chilly lows that can plunge to -20°C (-4°F), while the warmer days may reach up to 23°C (74°F). This month brings about 41 mm (1.6 in) of precipitation across approximately 5 days, contributing to a notably high average humidity of 86%. Prepare for a mix of cool and occasionally warm weather!

December Temperature in Lewistown

In December in Lewistown, the average temperature is 2°C (36°F), with maximums reaching up to 23°C (74°F) and minimums dropping as low as -20°C (-4°F). Be prepared for a wide range of temperatures when traveling to Lewistown during this month.

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 2°C (36°F), with highs reaching up to 23°C (74°F) and lows dropping to around -20°C (-4°F).
JanFebMarAprMayJunJulAugSepOctNovDec283144526576797571564236
Data source: Temperature data for Lewistown 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 Lewistown

In Lewistown in December, the precipitation amount is 41 mm (1.6 in) over a period of 5 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 41 mm (1.6 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec59571151001771059193811145241
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Lewistown

In Lewistown 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 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 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%80%80%80%82%83%81%80%76%76%85%86%
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 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 Lewistown, you can check the information here.

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 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579101110108643
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.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)59 mm (2.3 inches)82%moderate
February Weather-1°C (31°F)57 mm (2.2 inches)80%moderate
March Weather7°C (44°F)115 mm (4.5 inches)80%high
April Weather11°C (53°F)100 mm (4.0 inches)80%very high
May Weather18°C (66°F)177 mm (7.0 inches)82%very high
June Weather24°C (76°F)105 mm (4.1 inches)83%extreme
July Weather26°C (79°F)91 mm (3.6 inches)81%very high
August Weather24°C (76°F)93 mm (3.7 inches)80%very high
September Weather21°C (71°F)81 mm (3.2 inches)76%very high
October Weather14°C (57°F)114 mm (4.5 inches)76%high
November Weather5°C (42°F)52 mm (2.1 inches)85%moderate
December Weather2°C (36°F)41 mm (1.6 inches)86%moderate

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