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December Weather in Roundup, United States

Last updated: June 24, 2025

In December, the average temperature in Roundup, United States hovers around -2°C (29°F). While you might experience chilling lows of -27°C (-17°F), it's not uncommon for temperatures to peak at a mild 20°C (68°F). Expect 26 mm (1.0 in) of precipitation over approximately 7 days, and don’t forget to brace yourself for an average humidity of 85%.

December Temperature in Roundup

In December in Roundup, the average temperature is -2°C (29°F), with maximums reaching 20°C (68°F) and minimums plunging as low as -27°C (-17°F). Be prepared for a wide range of temperatures and pack accordingly for your travels!

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

The chart illustrates December temperature patterns in Roundup, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Roundup, December typically has an average temperature of -2°C (29°F), with highs reaching up to 20°C (68°F) and lows dropping to around -27°C (-17°F).
JanFebMarAprMayJunJulAugSepOctNovDec261935435466747261453629
Data source: Temperature data for Roundup 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 Roundup

In Roundup in December, the total precipitation amount is 26 mm (1.0 in) spread over a period of 7 days.

December Precipitation Trends in Roundup

The chart displays monthly precipitation patterns in Roundup, 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 Roundup, December typically receives around 26 mm (1.0 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec193627616569232038342326
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Roundup

In Roundup in December, humidity is 85%. With an average temperature of -2°C (29°F), this humidity feels like a chilling, damp blanket that clings to your skin, making travel uncomfortable and often prompting an urgent search for warmth and shelter.

December Average Humidity in Roundup

This chart illustrates the average monthly humidity levels in Roundup, 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 Roundup is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%85%77%72%75%78%79%76%67%69%78%85%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Roundup

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

Maximum UV Index Levels in Roundup for December

The chart shows the monthly maximum UV Index (UVI) for Roundup 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 Roundup typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec25599101098532
Data source: Roundup 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 Roundup Compares to Other Months

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

This table compares monthly weather conditions in Roundup, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (26°F)19 mm (0.7 inches)81%low
February Weather-7°C (20°F)36 mm (1.4 inches)85%moderate
March Weather2°C (35°F)27 mm (1.1 inches)77%moderate
April Weather6°C (43°F)61 mm (2.4 inches)72%very high
May Weather12°C (55°F)65 mm (2.6 inches)75%very high
June Weather19°C (66°F)69 mm (2.7 inches)78%very high
July Weather23°C (75°F)22 mm (0.9 inches)79%very high
August Weather22°C (72°F)20 mm (0.8 inches)76%very high
September Weather16°C (62°F)38 mm (1.5 inches)67%very high
October Weather7°C (46°F)34 mm (1.3 inches)69%moderate
November Weather2°C (37°F)23 mm (0.9 inches)78%moderate
December Weather-2°C (29°F)26 mm (1.0 inches)85%low

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