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September Weather in Dayton, United States

Last updated: June 24, 2025

In Dayton, United States, the average temperature in September hovers around 20°C (68°F), with minimums dipping to 4°C (39°F) and highs reaching up to 35°C (95°F). Expect a precipitation amount of 127 mm (5.0 in) over approximately 9 days, contributing to an average humidity of 75%. Whether you're exploring or relaxing, be prepared for a blend of warm days and refreshing showers!

September Temperature in Dayton

In September in Dayton, the average temperature is 20°C (68°F). Maximums can reach 35°C (95°F) and minimums can be as low as 4°C (39°F). This weather makes Dayton an ideal destination for travelers looking to enjoy mild 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 20°C (68°F), with highs reaching up to 35°C (95°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec212138486174767367513729
Data source: Temperature data for Dayton 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 Dayton

In Dayton in September, the precipitation amount is 127 mm (5.0 in) over a span of 9 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 127 mm (5.0 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec3243727216610989961271234137
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Dayton

In Dayton in September, humidity is 75%. With an average temperature of 20°C (68°F), this humidity feels like a warm, muggy embrace that can leave travelers feeling sticky and exhausted.

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 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%84%80%81%74%81%80%77%75%80%87%83%
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.
JanFebMarAprMayJunJulAugSepOctNovDec35589111098633
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.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (21°F)32 mm (1.3 inches)82%moderate
February Weather-6°C (21°F)42 mm (1.7 inches)84%moderate
March Weather3°C (38°F)72 mm (2.8 inches)80%moderate
April Weather9°C (48°F)72 mm (2.8 inches)81%very high
May Weather16°C (62°F)166 mm (6.5 inches)74%very high
June Weather23°C (74°F)109 mm (4.3 inches)80%extreme
July Weather24°C (76°F)89 mm (3.5 inches)80%very high
August Weather23°C (73°F)95 mm (3.8 inches)77%very high
September Weather20°C (68°F)127 mm (5.0 inches)75%very high
October Weather11°C (51°F)123 mm (4.8 inches)80%high
November Weather3°C (37°F)41 mm (1.6 inches)87%moderate
December Weather-2°C (29°F)37 mm (1.5 inches)83%moderate

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