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September Weather in Decatur, United States

Last updated: June 24, 2025

In September, the average temperature in Decatur, United States is a pleasant 23°C (74°F). However, prepare for a range: the minimum can dip to 7°C (45°F), while the maximum can soar to 35°C (95°F). Expect some moisture too, with an average precipitation of 71 mm (2.8 in) spread over 6 days, and humidity levels averaging around 64%. Stay comfortable and enjoy the variability!

September Temperature in Decatur

In September in Decatur, the average temperature is 23°C (74°F). The maximum can reach 35°C (95°F), and the minimum can be as low as 7°C (45°F). This diverse temperature range makes Decatur an ideal destination for travelers seeking to enjoy both warm days and cool evenings.

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 23°C (74°F), with highs reaching up to 35°C (95°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec384052576776807774604843
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.

September Precipitation in Decatur

In Decatur in September, the precipitation amount is 71 mm (2.8 in) over a span of 6 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 71 mm (2.8 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec849514318317589101153711626670
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Decatur

In Decatur in September, humidity is 64%. With an average temperature of 23°C (74°F), this humidity feels like a warm blanket wrapping around you, making outdoor exploration enjoyable yet slightly sticky, so it's best to stay hydrated and take breaks in the shade while traveling.

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 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%78%76%78%83%83%78%68%64%70%83%87%
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.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
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.
 TemperaturePrecipitationHumidityUV
January Weather3°C (38°F)84 mm (3.3 inches)81%moderate
February Weather5°C (41°F)95 mm (3.8 inches)78%high
March Weather11°C (52°F)143 mm (5.6 inches)76%high
April Weather14°C (57°F)183 mm (7.2 inches)78%very high
May Weather20°C (68°F)175 mm (6.9 inches)83%very high
June Weather25°C (76°F)88 mm (3.5 inches)83%extreme
July Weather26°C (80°F)101 mm (4.0 inches)78%extreme
August Weather25°C (77°F)153 mm (6.0 inches)68%very high
September Weather23°C (74°F)71 mm (2.8 inches)64%very high
October Weather16°C (60°F)162 mm (6.4 inches)70%high
November Weather9°C (48°F)66 mm (2.6 inches)83%moderate
December Weather6°C (44°F)70 mm (2.8 inches)87%moderate

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