January Weather in Decatur, United States

Last updated: June 24, 2025

In Decatur, United States, the average temperature in January hovers around 9°C (48°F), creating a cool climate. Expect a range that swings from a chilly -13°C (9°F) at its lowest to a mild 27°C (81°F) at its peak. During this month, precipitation averages 105 mm (4.1 in) spread across approximately 8 days, accompanied by an average humidity of 85%. Whether you’re looking to embrace the brisk air or prepare for the occasional shower, be ready for a diverse weather experience!

January Temperature in Decatur

In January in Decatur, the average temperature is 9°C (48°F), with maximums reaching 27°C (81°F) and minimums dropping as low as -13°C (9°F). This wide temperature range means travelers should be prepared for both warm and cold conditions during their visit.

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 9°C (48°F), with highs reaching up to 27°C (81°F) and lows dropping to around -13°C (9°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 105 mm (4.1 in) over the course of 8 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 105 mm (4.1 inches) of precipitation spread over approximately 8 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

January Humidity in Decatur

In Decatur in January humidity is 85%. With an average temperature of 9°C (48°F), this humidity feels like a damp chill enveloping you, making outdoor activities less enjoyable and requiring extra layers to stay warm and comfortable while traveling.

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 85%, 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	9°C (48°F)	105 mm (4.1 inches)	85%	moderate
February Weather	12°C (54°F)	156 mm (6.1 inches)	84%	high
March Weather	16°C (60°F)	116 mm (4.6 inches)	82%	very high
April Weather	18°C (65°F)	136 mm (5.4 inches)	82%	extreme
May Weather	23°C (74°F)	122 mm (4.8 inches)	82%	extreme
June Weather	26°C (79°F)	163 mm (6.4 inches)	79%	extreme
July Weather	27°C (81°F)	121 mm (4.8 inches)	82%	extreme
August Weather	27°C (81°F)	127 mm (5.0 inches)	77%	extreme
September Weather	25°C (78°F)	95 mm (3.8 inches)	74%	very high
October Weather	20°C (69°F)	100 mm (3.9 inches)	73%	very high
November Weather	13°C (55°F)	70 mm (2.7 inches)	85%	high
December Weather	11°C (52°F)	121 mm (4.8 inches)	88%	moderate