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December Weather in Great Falls, United States

Last updated: June 24, 2025

In December, the average temperature in Great Falls, United States hovers around 10°C (50°F), with a minimum dropping to -5°C (23°F) and a maximum soaring to 27°C (80°F). Expect around 131 mm (5.1 in) of precipitation over 9 days, contributing to an average humidity of 87%.

December Temperature in Great Falls

In December in Great Falls, the average temperature is 10°C (50°F), with maximums reaching up to 27°C (80°F) and minimums dropping as low as -5°C (23°F). This variation in temperature makes Great Falls a destination where travelers should be prepared for both warm days and chilly nights.

December Weather in Great Falls: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Great Falls, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Great Falls, December typically has an average temperature of 10°C (50°F), with highs reaching up to 27°C (80°F) and lows dropping to around -5°C (23°F).
JanFebMarAprMayJunJulAugSepOctNovDec475256647277817976675449
Data source: Temperature data for Great Falls 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 Great Falls

In Great Falls in December, the total precipitation amount is 131 mm (5.1 in) over a span of 9 days.

December Precipitation Trends in Great Falls

The chart displays monthly precipitation patterns in Great Falls, 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 Great Falls, December typically receives around 131 mm (5.1 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec89124831011121011241291027785131
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Great Falls

In Great Falls in December humidity is 87%. With an average temperature of 10°C (50°F), this humidity feels like a heavy cloak wrapping around you, making every step feel laborious and the air thick with moisture, challenging your comfort while traveling.

December Average Humidity in Great Falls

This chart illustrates the average monthly humidity levels in Great Falls, 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 Great Falls is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%85%84%82%83%82%80%74%75%79%87%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Great Falls

In Great Falls in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Great Falls for better planning.

Maximum UV Index Levels in Great Falls for December

The chart shows the monthly maximum UV Index (UVI) for Great Falls 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 Great Falls typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec47810101111109864
Data source: Great Falls 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 Great Falls Compares to Other Months

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

This table compares monthly weather conditions in Great Falls, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather8°C (47°F)89 mm (3.5 inches)86%moderate
February Weather11°C (52°F)124 mm (4.9 inches)85%high
March Weather13°C (56°F)83 mm (3.3 inches)84%very high
April Weather18°C (64°F)101 mm (4.0 inches)82%very high
May Weather22°C (72°F)112 mm (4.4 inches)83%very high
June Weather25°C (78°F)101 mm (4.0 inches)82%extreme
July Weather27°C (81°F)124 mm (4.9 inches)80%extreme
August Weather26°C (80°F)129 mm (5.1 inches)74%very high
September Weather24°C (76°F)102 mm (4.0 inches)75%very high
October Weather20°C (68°F)77 mm (3.0 inches)79%very high
November Weather12°C (54°F)85 mm (3.3 inches)87%high
December Weather10°C (50°F)131 mm (5.1 inches)87%moderate

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