January Weather in Decatur, United States

Last updated: June 24, 2025

In Decatur, United States, the average temperature in January hovers around 7°C (44°F), with a notable range between a chilly -14°C (7°F) and a warm 25°C (77°F). Expect an average precipitation of 110 mm (4.3 in) spread over 9 days, contributing to a high average humidity of 87%.

January Temperature in Decatur

In January in Decatur, the average temperature is 7°C (44°F). Maximum temperatures can reach 25°C (77°F), while minimums can drop as low as -14°C (7°F). This variation in temperatures makes it essential for travelers to be prepared for both warm and cold conditions while exploring Decatur.

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 (44°F), with highs reaching up to 25°C (77°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 110 mm (4.3 in) over the course of 9 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 110 mm (4.3 inches) of precipitation spread over approximately 9 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 87%. With an average temperature of 7°C (44°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities uncomfortable and requiring travelers to layer up to stay warm and dry.

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 87%, 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 (44°F)	110 mm (4.3 inches)	87%	moderate
February Weather	10°C (50°F)	181 mm (7.1 inches)	87%	high
March Weather	13°C (56°F)	178 mm (7.0 inches)	85%	very high
April Weather	17°C (62°F)	146 mm (5.8 inches)	82%	very high
May Weather	22°C (72°F)	108 mm (4.2 inches)	83%	extreme
June Weather	25°C (77°F)	147 mm (5.8 inches)	82%	extreme
July Weather	27°C (81°F)	105 mm (4.1 inches)	78%	extreme
August Weather	26°C (80°F)	112 mm (4.4 inches)	67%	very high
September Weather	24°C (76°F)	111 mm (4.4 inches)	64%	very high
October Weather	19°C (66°F)	122 mm (4.8 inches)	74%	high
November Weather	11°C (51°F)	74 mm (2.9 inches)	87%	moderate
December Weather	9°C (48°F)	152 mm (6.0 inches)	88%	moderate