September Weather in Decatur, United States

Last updated: June 24, 2025

The average temperature in Decatur, United States during September is a warm 24°C (75°F), with minimums dipping to 10°C (50°F) and maximums soaring up to 36°C (97°F). Expect 113 mm (4.4 in) of precipitation spread over 9 days, contributing to a comfortable average humidity of 82%.

September Temperature in Decatur

In September in Decatur, the average temperature is 24°C (75°F). The maximum can reach 36°C (97°F), while the minimum can be as low as 10°C (50°F). Whether you're looking to enjoy warm days or cool evenings, this climate provides a comfortable backdrop for exploring and enjoying all that Decatur has to offer.

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

The chart illustrates September 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, September typically has an average temperature of 24°C (75°F), with highs reaching up to 36°C (97°F) and lows dropping to around 10°C (50°F).

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

September Precipitation in Decatur

In Decatur in September, the precipitation amount is 113 mm (4.4 in) over a period of 9 days.

September Precipitation Trends in Decatur

The chart displays monthly precipitation patterns in Decatur, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Decatur, September typically receives around 113 mm (4.4 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

September Humidity in Decatur

In Decatur in September, humidity is 82%. With an average temperature of 24°C (75°F), this humidity feels like a warm embrace, making travel feel sticky and heavy on the skin, often requiring more frequent breaks and hydration.

September Average Humidity in Decatur

This chart illustrates the average monthly humidity levels in Decatur, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Decatur is approximately 82%, offering insight into how humid the weather typically is during this month.

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

September UV Index in Decatur

In Decatur in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Decatur.

Maximum UV Index Levels in Decatur for September

The chart shows the monthly maximum UV Index (UVI) for Decatur in September, 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 September, the maximum UV index in Decatur typically reaches 9, which falls under the very high exposure category.

Data source: Decatur September 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 September 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 September’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 September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	7°C (46°F)	105 mm (4.1 inches)	86%	moderate
February Weather	11°C (51°F)	147 mm (5.8 inches)	84%	high
March Weather	13°C (56°F)	129 mm (5.1 inches)	83%	very high
April Weather	17°C (62°F)	121 mm (4.8 inches)	81%	extreme
May Weather	22°C (71°F)	100 mm (4.0 inches)	81%	extreme
June Weather	24°C (76°F)	127 mm (5.0 inches)	81%	extreme
July Weather	26°C (80°F)	113 mm (4.4 inches)	83%	extreme
August Weather	26°C (79°F)	145 mm (5.7 inches)	81%	very high
September Weather	24°C (75°F)	113 mm (4.4 inches)	82%	very high
October Weather	19°C (66°F)	123 mm (4.9 inches)	78%	very high
November Weather	11°C (52°F)	80 mm (3.1 inches)	86%	high
December Weather	9°C (48°F)	137 mm (5.4 inches)	89%	moderate