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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 10°C (50°F). Expect a wide temperature range, with minimums dipping to -7°C (20°F) and maximums peaking at 28°C (83°F). Precipitation is modest, with an average of 49 mm (1.9 in) spread over 5 days, and the air carries a high humidity level of 85%.

December Temperature in Decatur

In December in Decatur, the average temperature is 10°C (50°F), with maximums reaching 28°C (83°F) and minimums dropping as low as -7°C (20°F). Travelers should be prepared for a wide range of temperatures and pack accordingly for both warm days and chilly nights.

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 10°C (50°F), with highs reaching up to 28°C (83°F) and lows dropping to around -7°C (20°F).
JanFebMarAprMayJunJulAugSepOctNovDec454859647481858478665550
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 49 mm (1.9 in) spread over a period of 5 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 49 mm (1.9 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec51788591135864482811215049
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 85%. With an average temperature of 10°C (50°F), this humidity feels like a heavy, damp blanket surrounding you, making travel feel sluggish and uncomfortable as you navigate through the thick, moist air.

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 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec77%76%74%75%80%80%75%67%64%70%82%85%
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 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 Decatur for better planning.

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 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111111110864
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 Weather7°C (45°F)51 mm (2.0 inches)77%moderate
February Weather9°C (48°F)78 mm (3.1 inches)76%high
March Weather15°C (59°F)85 mm (3.3 inches)74%very high
April Weather18°C (64°F)91 mm (3.6 inches)75%very high
May Weather23°C (74°F)135 mm (5.3 inches)80%extreme
June Weather27°C (81°F)86 mm (3.4 inches)80%extreme
July Weather29°C (85°F)44 mm (1.7 inches)75%extreme
August Weather29°C (84°F)82 mm (3.2 inches)67%extreme
September Weather26°C (78°F)81 mm (3.2 inches)64%very high
October Weather19°C (67°F)121 mm (4.8 inches)70%very high
November Weather13°C (55°F)50 mm (2.0 inches)82%high
December Weather10°C (50°F)49 mm (1.9 inches)85%moderate

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