January Weather in Decatur, United States

Last updated: June 24, 2025

In Decatur, United States, the average temperature during January hovers around 7°C (45°F). Be prepared for a range, as temperatures can dip to a brisk -14°C (7°F) or rise to a pleasant 26°C (79°F). Expect about 51 mm (2.0 in) of precipitation spread over 7 days, with an average humidity of 77%, creating a uniquely refreshing atmosphere.

January Temperature in Decatur

In January in Decatur, the average temperature is 7°C (45°F), with maximums reaching 26°C (79°F) and minimums dropping as low as -14°C (7°F). Be prepared for a wide range of temperatures, making it essential to pack layers for your travels.

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

The chart illustrates January 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, January typically has an average temperature of 7°C (45°F), with highs reaching up to 26°C (79°F) and lows dropping to around -14°C (7°F).

Data source: Temperature data for Decatur generated using information from the Copernicus Climate Change Service.

January Precipitation in Decatur

In Decatur in January, the precipitation amount is 51 mm (2.0 in) over a period of 7 days.

January Precipitation Trends in Decatur

The chart displays monthly precipitation patterns in Decatur, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Decatur, January typically receives around 51 mm (2.0 inches) of precipitation spread over approximately 7 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Decatur

In Decatur in January, humidity is 77%. With an average temperature of 7°C (45°F), this humidity feels like a damp chill that clings to your skin, making it important to dress in layers for comfort while exploring the area.

January Average Humidity in Decatur

This chart illustrates the average monthly humidity levels in Decatur, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Decatur is approximately 77%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Decatur

In Decatur in January, 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 January

The chart shows the monthly maximum UV Index (UVI) for Decatur in January, 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 January, the maximum UV index in Decatur typically reaches 4, which falls under the moderate exposure category.

Data source: Decatur January 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 January 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 January’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 January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	7°C (45°F)	51 mm (2.0 inches)	77%	moderate
February Weather	9°C (48°F)	78 mm (3.1 inches)	76%	high
March Weather	15°C (59°F)	85 mm (3.3 inches)	74%	very high
April Weather	18°C (64°F)	91 mm (3.6 inches)	75%	very high
May Weather	23°C (74°F)	135 mm (5.3 inches)	80%	extreme
June Weather	27°C (81°F)	86 mm (3.4 inches)	80%	extreme
July Weather	29°C (85°F)	44 mm (1.7 inches)	75%	extreme
August Weather	29°C (84°F)	82 mm (3.2 inches)	67%	extreme
September Weather	26°C (78°F)	81 mm (3.2 inches)	64%	very high
October Weather	19°C (67°F)	121 mm (4.8 inches)	70%	very high
November Weather	13°C (55°F)	50 mm (2.0 inches)	82%	high
December Weather	10°C (50°F)	49 mm (1.9 inches)	85%	moderate