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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 8°C (47°F), with fluctuations that can dip as low as -8°C (17°F) and peak at a comfortable 23°C (73°F). Expect about 133 mm (5.2 in) of precipitation over 10 days, contributing to an average humidity of 88%. Prepare for a mix of chilly and mild days!

December Temperature in Decatur

In December in Decatur, the average temperature is 8°C (47°F). Maximum temperatures can reach 23°C (73°F), while minimums can drop as low as -8°C (17°F). Travelers should be prepared for a wide range of temperatures and pack accordingly.

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 8°C (47°F), with highs reaching up to 23°C (73°F) and lows dropping to around -8°C (17°F).
JanFebMarAprMayJunJulAugSepOctNovDec434854607076807875655046
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 total precipitation amount is 133 mm (5.2 in) spread over a period of 10 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 133 mm (5.2 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec981731621521201041081149312478133
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 88%. With an average temperature of 8°C (47°F), this humidity feels like a thick, damp blanket wrapping around you, making even short walks feel heavy and uninviting 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 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%82%85%85%83%76%76%80%88%88%
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 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 Decatur, you can check the information here.

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 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36810111111109753
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 Weather6°C (43°F)98 mm (3.8 inches)86%moderate
February Weather9°C (48°F)173 mm (6.8 inches)86%high
March Weather12°C (54°F)162 mm (6.4 inches)86%very high
April Weather16°C (61°F)152 mm (6.0 inches)82%very high
May Weather21°C (71°F)120 mm (4.7 inches)85%extreme
June Weather24°C (76°F)104 mm (4.1 inches)85%extreme
July Weather27°C (80°F)108 mm (4.2 inches)83%extreme
August Weather26°C (79°F)114 mm (4.5 inches)76%very high
September Weather24°C (75°F)93 mm (3.7 inches)76%very high
October Weather18°C (65°F)124 mm (4.9 inches)80%high
November Weather10°C (51°F)78 mm (3.1 inches)88%moderate
December Weather8°C (47°F)133 mm (5.2 inches)88%moderate

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