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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 9°C (48°F). Expect a chilly minimum of -6°C (21°F) and a pleasant maximum of 23°C (73°F) throughout the month. Prepare for some wet days, as precipitation totals 152 mm (6.0 in) across 12 days, coupled with a high average humidity of 88%.

December Temperature in Decatur

In December in Decatur, the average temperature is 9°C (48°F). The maximum can reach 23°C (73°F), while the minimum can drop as low as -6°C (21°F). Be prepared for a wide range of temperatures during your visit!

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 9°C (48°F), with highs reaching up to 23°C (73°F) and lows dropping to around -6°C (21°F).
JanFebMarAprMayJunJulAugSepOctNovDec444956627277808075665148
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 152 mm (6.0 in), which falls over the course of 12 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 152 mm (6.0 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec11018117814610814710511211112274152
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 9°C (48°F), this humidity feels like a damp chill settling into your bones, making outdoor exploration feel heavy and oppressive.

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.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%85%82%83%82%78%67%64%75%87%89%
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.
JanFebMarAprMayJunJulAugSepOctNovDec47810111111109754
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 (44°F)110 mm (4.3 inches)87%moderate
February Weather10°C (50°F)181 mm (7.1 inches)87%high
March Weather13°C (56°F)178 mm (7.0 inches)85%very high
April Weather17°C (62°F)146 mm (5.8 inches)82%very high
May Weather22°C (72°F)108 mm (4.2 inches)83%extreme
June Weather25°C (77°F)147 mm (5.8 inches)82%extreme
July Weather27°C (81°F)105 mm (4.1 inches)78%extreme
August Weather26°C (80°F)112 mm (4.4 inches)67%very high
September Weather24°C (76°F)111 mm (4.4 inches)64%very high
October Weather19°C (66°F)122 mm (4.8 inches)74%high
November Weather11°C (51°F)74 mm (2.9 inches)87%moderate
December Weather9°C (48°F)152 mm (6.0 inches)88%moderate

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