September weather forecast
Detroit, IL

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Weather in September

September, the first month of the autumn in Detroit, is still a warm month, with temperature in the range of an average low of 58.6°F (14.8°C) and an average high of 78.3°F (25.7°C).

Temperature

The high-temperature average in September for Detroit is a still moderately hot 78.3°F (25.7°C), staying closely aligned with August's conditions. Detroit's September nights cool down to an average low-temperature of 58.6°F (14.8°C).

Humidity

In September, the average relative humidity is 74%.

Rainfall

In Detroit, during September, the rain falls for 10.5 days and regularly aggregates up to 1.65" (42mm) of precipitation. In Detroit, during the entire year, the rain falls for 128.8 days and collects up to 18.35" (466mm) of precipitation.

Snowfall

In Detroit, snow does not fall in May through October.

Daylight

The average length of the day in September is 12h and 26min.
On the first day of September, sunrise is at 6:31 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:46 pm CDT.

Sunshine

The average sunshine in September is 9.5h.

UV index

The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: In September, a daily maximum UV index of 5 leads to the following instructions:
Exercise prevention - Precautions against solar damage are endorsed. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Experience reduced UV exposure by about half when donning a wide-brim hat.
Updated: Jul 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

During September, Detroit experiences an average high-temperature of 78.3°F (25.7°C) and a low-temperature of 58.6°F (14.8°C). In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which combines relative humidity and air temperature, is calculated to be 91.4°F (33°C).

What is the average humidity in September?

The average relative humidity in September is 74%.

How much does it rain in September?

In Detroit, in September, it is raining for 10.5 days, with typically 1.65" (42mm) of accumulated precipitation.

When it does not snow?

May through October are months without snowfall in Detroit.

What is the average length of the day in September in Detroit?

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

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:31 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:46 pm CDT.

How many hours of sunshine does Detroit have in September?

In Detroit, the average sunshine duration in September is 9.5h.

What is the UV index reading in September?

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
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
Detroit, IL

Average temperature in September - Detroit, IL
  • Average high temperature in September: 78.3°F

The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (33.8°F).

  • Average low temperature in September: 58.6°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).

Average pressure in September
Detroit, IL

Average pressure in September - Detroit, IL
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Detroit, IL

Average wind speed in September - Detroit, IL
  • Average wind speed in September: 6.8mph

The windiest months (with the highest average wind speed) are January, February and April (9.8mph).
The calmest month (with the lowest average wind speed) is July (6mph).

Average humidity in September
Detroit, IL

Average humidity in September - Detroit, IL
  • Average humidity in September: 74%

The months with the highest relative humidity are June and July (81%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Detroit, IL

Average rainfall in September - Detroit, IL
  • Average rainfall in September: 1.65"

The wettest month (with the highest rainfall) is May (2.44").
The driest month (with the least rainfall) is February (0.75").

Average rainfall days in September
Detroit, IL

Average rainfall days in September - Detroit, IL
  • Average rainfall days in September: 10.5 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (4.5 days).

Average snowfall in September
Detroit, IL

Average snowfall in September - Detroit, IL
  • 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, September and October (0").

Average snowfall days in September
Detroit, IL

Average snowfall days in September - Detroit, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (6.3 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
Detroit, IL

Average daylight in September / Average sunshine in September - Detroit, IL
  • 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: 9h and 3min

The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in September
Detroit, IL

Average sunshine days in September - Detroit, IL
  • Average sunshine days in September: 17.3 days

The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is June (12.3 days).

Average UV index in September
Detroit, IL

Average UV index in September - Detroit, IL
  • Average UV index in September: 5

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
Detroit, IL

Average cloud cover in September - Detroit, IL
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).

Average visibility in September
Detroit, IL

Average visibility in September - Detroit, IL
  • 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).

Detroit, Illinois, USA

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