September Weather in Dayton, United States

Last updated: June 24, 2025

In Dayton, United States, the average temperature in September hovers around 19°C (67°F), with a minimum dipping to 2°C (35°F) and a maximum soaring to 37°C (99°F). Expect light precipitation of about 6 mm (0.2 in) over just 1 day during the month, while the average humidity rests comfortably at 41%.

September Temperature in Dayton

In September in Dayton, the average temperature is 19°C (67°F). Maximums can reach 37°C (99°F), while minimums can drop to as low as 2°C (35°F). Be prepared for a wide range of temperatures when traveling during this month.

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 19°C (67°F), with highs reaching up to 37°C (99°F) and lows dropping to around 2°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 precipitation amount is 6 mm (0.2 in) over the course of 1 day.

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 6 mm (0.2 inches) of precipitation spread over approximately 1 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Dayton

In Dayton in September, humidity is 41%. With an average temperature of 19°C (67°F), this humidity feels like a refreshing breeze, making it ideal for exploring outdoor attractions and enjoying leisurely strolls without feeling overheated.

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 41%, 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 reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. 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 10, 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	1°C (34°F)	73 mm (2.9 inches)	85%	moderate
February Weather	2°C (36°F)	70 mm (2.8 inches)	87%	high
March Weather	5°C (41°F)	52 mm (2.1 inches)	84%	very high
April Weather	10°C (50°F)	25 mm (1.0 inches)	78%	very high
May Weather	14°C (58°F)	26 mm (1.0 inches)	64%	extreme
June Weather	21°C (69°F)	6 mm (0.2 inches)	56%	extreme
July Weather	25°C (78°F)	8 mm (0.3 inches)	44%	extreme
August Weather	24°C (76°F)	9 mm (0.3 inches)	34%	extreme
September Weather	19°C (67°F)	6 mm (0.2 inches)	41%	very high
October Weather	11°C (53°F)	29 mm (1.1 inches)	60%	high
November Weather	6°C (43°F)	30 mm (1.2 inches)	81%	moderate
December Weather	1°C (34°F)	49 mm (1.9 inches)	82%	moderate