September Weather in Dayton, United States

Last updated: June 24, 2025

In Dayton, United States, the average temperature in September settles at 14°C (58°F). This month can experience a dramatic range, with minimums dropping to -6°C (22°F) and soaring to maximums of 36°C (97°F). Expect about 63 mm (2.5 in) of precipitation over roughly 8 days, accompanied by an average humidity level of 79%.

September Temperature in Dayton

In September in Dayton, the average temperature is 14°C (58°F). The maximum can reach 36°C (97°F) and the minimum can be as low as -6°C (22°F). Pack accordingly to enjoy a range of weather conditions while exploring Dayton.

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 14°C (58°F), with highs reaching up to 36°C (97°F) and lows dropping to around -6°C (22°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 precipitation amount is 63 mm (2.5 in) spread over 8 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 63 mm (2.5 inches) of precipitation spread over approximately 8 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 79%. With an average temperature of 14°C (58°F), this humidity feels like an oppressive blanket wrapped around you, making even the mild temperatures feel heavier and more stifling for traveling.

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 79%, 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 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to 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 8, which falls under the very 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	-4°C (25°F)	26 mm (1.0 inches)	78%	moderate
February Weather	-7°C (20°F)	45 mm (1.8 inches)	79%	moderate
March Weather	0°C (33°F)	56 mm (2.2 inches)	71%	high
April Weather	4°C (39°F)	97 mm (3.8 inches)	70%	very high
May Weather	10°C (50°F)	109 mm (4.3 inches)	75%	very high
June Weather	16°C (61°F)	84 mm (3.3 inches)	82%	extreme
July Weather	20°C (69°F)	63 mm (2.5 inches)	84%	very high
August Weather	19°C (66°F)	48 mm (1.9 inches)	85%	very high
September Weather	14°C (58°F)	63 mm (2.5 inches)	79%	very high
October Weather	5°C (41°F)	67 mm (2.6 inches)	75%	moderate
November Weather	0°C (33°F)	37 mm (1.5 inches)	75%	moderate
December Weather	-3°C (27°F)	35 mm (1.4 inches)	81%	low