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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 24°C (76°F). Expect lows that can drop to 11°C (52°F) and highs soaring up to 36°C (97°F). During this month, precipitation averages around 111 mm (4.4 in) over 8 days, accompanied by an average humidity of 64%. Enjoy the balanced climate and prepare for occasional rain!

September Temperature in Decatur

In September in Decatur, the average temperature is 24°C (76°F). Maximum temperatures can reach 36°C (97°F), while minimums can dip as low as 11°C (52°F). This diverse temperature range makes Decatur an ideal destination for travelers seeking both warm days and cooler 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 24°C (76°F), with highs reaching up to 36°C (97°F) and lows dropping to around 11°C (52°F).
JanFebMarAprMayJunJulAugSepOctNovDec444956627277808075665148
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 111 mm (4.4 in) spread over 8 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 111 mm (4.4 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec11018117814610814710511211112274152
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 24°C (76°F), this humidity feels like a warm, sticky embrace, making travel slightly uncomfortable but still enjoyable, as you may find yourself yearning for a refreshing breeze or a quick dip in the water.

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.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%85%82%83%82%78%67%64%75%87%89%
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.
JanFebMarAprMayJunJulAugSepOctNovDec47810111111109754
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 Weather7°C (44°F)110 mm (4.3 inches)87%moderate
February Weather10°C (50°F)181 mm (7.1 inches)87%high
March Weather13°C (56°F)178 mm (7.0 inches)85%very high
April Weather17°C (62°F)146 mm (5.8 inches)82%very high
May Weather22°C (72°F)108 mm (4.2 inches)83%extreme
June Weather25°C (77°F)147 mm (5.8 inches)82%extreme
July Weather27°C (81°F)105 mm (4.1 inches)78%extreme
August Weather26°C (80°F)112 mm (4.4 inches)67%very high
September Weather24°C (76°F)111 mm (4.4 inches)64%very high
October Weather19°C (66°F)122 mm (4.8 inches)74%high
November Weather11°C (51°F)74 mm (2.9 inches)87%moderate
December Weather9°C (48°F)152 mm (6.0 inches)88%moderate

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