September weather forecast
Dayton, OH

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The Maimi and Mad rivers converge to flow through Dayton city, Ohio
The Maimi and Mad rivers converge to flow through Dayton city, Ohio

Weather in September

September marks the advent of fall in Dayton. The city's weather starts cooling significantly, providing a welcome relief from the summer heat. The daylight hours shorten, indicating a transitional phase. September also sees reduced rainfall, making it a preferable time for outdoor activities. The temperature range drops to 57°F (13.9°C) which signifies a marked departure from the soaring summer heat.

Temperature

Dayton marks the arrival of September with an average high-temperature of a still moderately hot 75°F (23.9°C), hardly different from August's 80.2°F (26.8°C). Nighttime temperatures consistently average a moderate 57°F (13.9°C) during September.

Humidity

The average relative humidity in September is 77%.

Rainfall

The months with the least rainfall are September and November Rain falls for 12.5 days and accumulates 1.5" (38mm) of rain.

Snowfall

May through September are months without snowfall.

Daylight

In Dayton, the average length of the day in September is 12h and 26min.
On the first day of September, sunrise is at 7:05 am and sunset at 8:07 pm. On the last day of the month, sunrise is at 7:32 am and sunset at 7:20 pm EDT.

Sunshine

The average sunshine in September is 8.3h.

UV index

In Dayton, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.
Note: A typical high UV index of 4 in September suggests the following recommendations:
Undertake precautions - Obligation exists to protect against skin and eye damage. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.

Frequently asked questions

What are the temperatures in September?

The average high-temperature, in September, in Dayton, is 75°F (23.9°C), while the average low-temperature is 57°F (13.9°C). In July, the average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, is appraised at 87.8°F (31°C).

What is the average humidity in September in Dayton?

The average relative humidity in September is 77%.

What is the driest month?

The months with the least rainfall are September and November Rain falls for 12.5 days and accumulates 1.5" (38mm) of rain.

How many days does it rain in September?

In September, the rain falls for 12.5 days. Throughout September, 1.5" (38mm) of precipitation is accumulated.

When it does not snow?

In Dayton, snow does not fall in May through September.

Does it snow in September?

In Dayton, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In Dayton, the average day length in September is 12h and 26min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 7:05 am and sunset at 8:07 pm. On the last day of the month, sunrise is at 7:32 am and sunset at 7:20 pm EDT.

How long on average sun shines in September?

In Dayton, the average sunshine duration in September is 8.3h.

What is the UV index intensity in September?

In September, the average daily maximum UV index in Dayton is 4. A UV Index value of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Dayton, OH

Average temperature in September - Dayton, OH
  • Average high temperature in September: 75°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (33.6°F).

  • Average low temperature in September: 57°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (21.7°F).

Average pressure in September
Dayton, OH

Average pressure in September - Dayton, OH
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in September
Dayton, OH

Average wind speed in September - Dayton, OH
  • Average wind speed in September: 6.3mph

The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is August (5.7mph).

Average humidity in September
Dayton, OH

Average humidity in September - Dayton, OH
  • Average humidity in September: 77%

The months with the highest relative humidity are January, February and December (82%).
The month with the lowest relative humidity is October (74%).

Average rainfall in September
Dayton, OH

Average rainfall in September - Dayton, OH
  • Average rainfall in September: 1.5"

The wettest month (with the highest rainfall) is May (3.35").
The driest months (with the least rainfall) are September and November (1.5").

Average rainfall days in September
Dayton, OH

Average rainfall days in September - Dayton, OH
  • Average rainfall days in September: 12.5 days

The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is February (7.5 days).

Average snowfall in September
Dayton, OH

Average snowfall in September - Dayton, OH
  • Average snowfall in September: 0"

The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Dayton, OH

Average snowfall days in September - Dayton, OH
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (8.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Dayton, OH

Average daylight in September / Average sunshine in September - Dayton, OH
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 8h and 2min

The months with the most sunshine are June and July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in September
Dayton, OH

Average sunshine days in September - Dayton, OH
  • Average sunshine days in September: 16.1 days

The month with the most sunshine days is November (18.9 days).
The month with the least sunshine days is May (9.8 days).

Average UV index in September
Dayton, OH

Average UV index in September - Dayton, OH
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Dayton, OH

Average cloud cover in September - Dayton, OH
  • Average cloud cover in September: 33

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in September
Dayton, OH

Average visibility in September - Dayton, OH
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Dayton, Ohio, USA

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