September Weather in Dayton, United States

Last updated: June 24, 2025

In September, the average temperature in Dayton, United States is a pleasant 18°C (64°F). However, you can expect a range, with minimums dipping to 1°C (35°F) and maximums soaring up to 33°C (91°F). Be prepared for 112 mm (4.4 in) of precipitation over approximately 10 days, contributing to an average humidity of 81%.

September Temperature in Dayton

In September in Dayton, the average temperature is 18°C (64°F). Maximums can reach 33°C (91°F), and minimums can be as low as 1°C (35°F). Travelers should be prepared for a range of temperatures and pack accordingly for both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Dayton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Dayton, September typically has an average temperature of 18°C (64°F), with highs reaching up to 33°C (91°F) and lows dropping to around 1°C (35°F).

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

September Precipitation in Dayton

In Dayton in September, the total precipitation amount is 112 mm (4.4 in) over the course of 10 days.

September Precipitation Trends in Dayton

The chart displays monthly precipitation patterns in Dayton, 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 Dayton, September typically receives around 112 mm (4.4 inches) of precipitation spread over approximately 10 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 Dayton

In Dayton in September, humidity is 81%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making travel both refreshing and slightly stifling at the same time.

September Average Humidity in Dayton

This chart illustrates the average monthly humidity levels in Dayton, 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 Dayton is approximately 81%, 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 Dayton

In Dayton in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Dayton.

Maximum UV Index Levels in Dayton for September

The chart shows the monthly maximum UV Index (UVI) for Dayton 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 Dayton typically reaches 7, which falls under the high exposure category.

Data source: Dayton 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 Dayton Compares to Other Months

Weather in Dayton varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Dayton, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Dayton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-9°C (16°F)	22 mm (0.9 inches)	87%	low
February Weather	-9°C (16°F)	29 mm (1.1 inches)	90%	moderate
March Weather	0°C (33°F)	53 mm (2.1 inches)	85%	moderate
April Weather	6°C (43°F)	93 mm (3.6 inches)	84%	high
May Weather	15°C (59°F)	108 mm (4.2 inches)	78%	very high
June Weather	22°C (71°F)	77 mm (3.0 inches)	80%	very high
July Weather	23°C (74°F)	99 mm (3.9 inches)	81%	very high
August Weather	21°C (71°F)	144 mm (5.7 inches)	81%	very high
September Weather	18°C (64°F)	112 mm (4.4 inches)	81%	high
October Weather	9°C (48°F)	103 mm (4.1 inches)	84%	moderate
November Weather	0°C (33°F)	34 mm (1.3 inches)	88%	moderate
December Weather	-5°C (23°F)	47 mm (1.8 inches)	84%	low