September weather forecast
Greenville, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Greenville, Illinois, with temperature in the range of an average high of 77.9°F (25.5°C) and an average low of 59.5°F (15.3°C).

Temperature

In September, Greenville's weather conditions record an average high-temperature of a still warm 77.9°F (25.5°C), demonstrating little divergence from the preceding month. In the month of September, Greenville records a consistent average low-temperature of 59.5°F (15.3°C).

Humidity

In September, the average relative humidity is 75%.

Rainfall

In Greenville, in September, it is raining for 11.5 days, with typically 1.5" (38mm) of accumulated precipitation. Throughout the year, there are 137.9 rainfall days, and 24.88" (632mm) of precipitation is accumulated.

Snowfall

In Greenville, snow does not fall in April through October.

Daylight

In Greenville, the average length of the day in September is 12h and 26min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:27 pm. On the last day of September, in Greenville, sunrise is at 6:53 am and sunset at 6:41 pm CDT.

Sunshine

In Greenville, the average sunshine in September is 9.3h.

UV index

In Greenville, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: The maximum UV index, 5 during September, leads to the following recommendations:
Make use of precautions - Suggestions to resist sunburn are communicated. When the Sun is at its strongest around midday, find shade and limit exposure. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Updated: Jul 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in September?

During September, Greenville experiences an average high-temperature of 77.9°F (25.5°C) and a low-temperature of 59.5°F (15.3°C). The average heat index (a.k.a. 'feels like', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in August is computed to be 91.4°F (33°C).

What is the average humidity in September in Greenville?

The average relative humidity in September is 75%.

How much does it rain in September?

In September, the rain falls for 11.5 days. Throughout September, 1.5" (38mm) of precipitation is accumulated.

When it does not snow?

April through October are months without snowfall.

How many hours of daylight does Greenville have in September?

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

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:27 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:41 pm CDT.

How many hours of sunshine does Greenville have in September?

In Greenville, the average sunshine duration in September is 9.3h.

How high is the UV index in September?

In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe 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
Greenville, IL

Average temperature in September - Greenville, IL
  • Average high temperature in September: 77.9°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 (36.1°F).

  • Average low temperature in September: 59.5°F

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

Average pressure in September
Greenville, IL

Average pressure in September - Greenville, IL
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Greenville, IL

Average wind speed in September - Greenville, IL
  • Average wind speed in September: 6.4mph

The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).

Average humidity in September
Greenville, IL

Average humidity in September - Greenville, IL
  • Average humidity in September: 75%

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

Average rainfall in September
Greenville, IL

Average rainfall in September - Greenville, IL
  • Average rainfall in September: 1.5"

The wettest month (with the highest rainfall) is June (3.43").
The driest month (with the least rainfall) is February (1.26").

Average rainfall days in September
Greenville, IL

Average rainfall days in September - Greenville, IL
  • Average rainfall days in September: 11.5 days

The month with the highest number of rainy days is May (17.2 days).
The month with the least rainy days is January (6.3 days).

Average snowfall in September
Greenville, IL

Average snowfall in September - Greenville, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is December (1.89").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Greenville, IL

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

The month with the highest number of snowfall days is January (5.8 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
Greenville, IL

Average daylight in September / Average sunshine in September - Greenville, 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 30min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is June (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 30min).

Average sunshine days in September
Greenville, IL

Average sunshine days in September - Greenville, IL
  • Average sunshine days in September: 16.1 days

The month with the most sunshine days is December (20 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in September
Greenville, IL

Average UV index in September - Greenville, 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
Greenville, IL

Average cloud cover in September - Greenville, 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
Greenville, IL

Average visibility in September - Greenville, 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).

Greenville, Illinois, USA

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