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December Weather in Decatur, United States

Last updated: June 24, 2025

In December, the average temperature in Decatur, United States hovers around 1°C (34°F). Temperatures can fluctuate significantly, with a minimum of -24°C (-10°F) and a maximum reaching up to 17°C (63°F). Expect 65 mm (2.6 in) of precipitation spread across 11 days, accompanied by a high average humidity of 86%. Prepare accordingly for the chill and moisture!

December Temperature in Decatur

In December in Decatur, the average temperature is 1°C (34°F), with maximums reaching 17°C (63°F) and minimums dropping as low as -24°C (-10°F). It's advisable to pack layers and prepare for a wide range of temperatures when traveling during this time.

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

The chart illustrates December temperature patterns in Decatur, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Decatur, December typically has an average temperature of 1°C (34°F), with highs reaching up to 17°C (63°F) and lows dropping to around -24°C (-10°F).
JanFebMarAprMayJunJulAugSepOctNovDec272838476071757266544033
Data source: Temperature data for Decatur 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 Decatur

In Decatur in December, the precipitation amount is 65 mm (2.6 in) over a span of 11 days.

December Precipitation Trends in Decatur

The chart displays monthly precipitation patterns in Decatur, 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 Decatur, December typically receives around 65 mm (2.6 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec74779010916913711995841447365
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Decatur

In Decatur in December, humidity is 86%. With an average temperature of 1°C (34°F), this humidity feels like a chilling embrace, making outdoor adventures brisk and invigorating but challenging for travel.

December Average Humidity in Decatur

This chart illustrates the average monthly humidity levels in Decatur, 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 Decatur is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%86%87%81%82%81%79%78%81%89%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Decatur

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

Maximum UV Index Levels in Decatur for December

The chart shows the monthly maximum UV Index (UVI) for Decatur 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 Decatur typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35689101098642
Data source: Decatur 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 Decatur Compares to Other Months

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

This table compares monthly weather conditions in Decatur, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)74 mm (2.9 inches)85%moderate
February Weather-2°C (29°F)77 mm (3.0 inches)85%moderate
March Weather3°C (39°F)90 mm (3.5 inches)86%high
April Weather8°C (48°F)109 mm (4.3 inches)87%very high
May Weather16°C (61°F)168 mm (6.6 inches)81%very high
June Weather22°C (71°F)137 mm (5.4 inches)82%very high
July Weather24°C (75°F)119 mm (4.7 inches)81%very high
August Weather22°C (72°F)95 mm (3.7 inches)79%very high
September Weather19°C (67°F)84 mm (3.3 inches)78%very high
October Weather12°C (54°F)144 mm (5.7 inches)81%high
November Weather4°C (40°F)73 mm (2.9 inches)89%moderate
December Weather1°C (34°F)65 mm (2.6 inches)86%low

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