September weather forecast
Belleville, IL

Share

Weather in September

September brings a nuanced change to Belleville's weather. As summer waves a warm goodbye, September gently escorts the city into the embrace of fall. The drop in temperatures becomes apparent, with the average high temperature comfortably resting at 79.3°F (26.3°C). Belleville fingers the edges of summer while also ushering in a beautiful fall season filled with color and tranquility. Displaying a unique blend of summer warmth and autumn coolness, September stands as a transitional treasure in Belleville's weather calendar.

Temperature

The arrival of September is marked by an average high-temperature of a still warm 79.3°F (26.3°C), bearing a close resemblance to August. The low-temperature average for Belleville during September stands at a mild 59.9°F (15.5°C).

Humidity

The average relative humidity in September is 75%.

Rainfall

In Belleville, in September, it is raining for 12.5 days, with typically 2.2" (56mm) of accumulated precipitation. In Belleville, during the entire year, the rain falls for 147.1 days and collects up to 35.43" (900mm) of precipitation.

Snowfall

April through October are months without snowfall in Belleville.

Daylight

The average length of the day in September in Belleville is 12h and 25min.
On the first day of September in Belleville, Illinois, sunrise is at 6:29 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:43 pm CDT.

Sunshine

The average sunshine in September is 9.2h.

UV index

In Belleville, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: In September, an average UV index of 5 transforms into the following instructions:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. Notice! The UV radiation of the Sun can be intensified nearly twofold due to the reflective quality of snow.
[Resources]

Frequently asked questions

What are September temperatures in Belleville?

September temperatures in Belleville vary between a high-temperature of 79.3°F (26.3°C) and a low-temperature of 59.9°F (15.5°C). In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which represents the influence of relative humidity on air temperature, is estimated at 95°F (35°C).

What is the average humidity in September in Belleville?

In Belleville, the average relative humidity in September is 75%.

How many days does it rain in September in Belleville?

In Belleville, Illinois, in September, it is raining for 12.5 days, with typically 2.2" (56mm) of accumulated precipitation.

When it does not snow in Belleville?

April through October are months without snowfall.

How many hours of daylight does Belleville have in September?

In Belleville, the average day length in September is 12h and 25min.

What time are sunrise and sunset in September in Belleville?

On the first day of September, sunrise is at 6:29 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:43 pm CDT.

How many hours of sunshine does Belleville have in September?

The average sunshine duration in September is 9.2h.

What is the UV index intensity in September in Belleville?

In Belleville, Illinois, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to the Sun's 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
Belleville, IL

Average temperature in September - Belleville, IL
  • Average high temperature in September: 79.3°F

The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is January (37.8°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).

[Resources]

Average pressure in September
Belleville, IL

Average pressure in September - Belleville, IL
  • Average pressure in September: 30.02"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).

[Resources]

Average wind speed in September
Belleville, IL

Average wind speed in September - Belleville, IL
  • Average wind speed in September: 6.1mph

The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).

[Resources]

Average humidity in September
Belleville, IL

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

The months with the highest relative humidity are May and July (79%).
The month with the lowest relative humidity is October (71%).

[Resources]

Average rainfall in September
Belleville, IL

Average rainfall in September - Belleville, IL
  • Average rainfall in September: 2.2"

The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.93").

[Resources]

Average rainfall days in September
Belleville, IL

Average rainfall days in September - Belleville, IL
  • Average rainfall days in September: 12.5 days

The month with the highest number of rainy days is May (16.4 days).
The month with the least rainy days is January (6.8 days).

[Resources]

Average snowfall in September
Belleville, IL

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

The month with the highest snowfall is January (2.4").
The months with the least snowfall are April, May, June, July, August, September and October (0").

[Resources]

Average snowfall days in September
Belleville, IL

Average snowfall days in September - Belleville, IL
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are May, June, July and August (0 days).

[Resources]

Average daylight in September /
Average sunshine in September
Belleville, IL

Average daylight in September / Average sunshine in September - Belleville, IL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

[Resources]

Average sunshine days in September
Belleville, IL

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

The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is May (12.3 days).

[Resources]

Average UV index in September
Belleville, IL

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

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

[Resources]

Average cloud cover in September
Belleville, IL

Average cloud cover in September - Belleville, IL
  • Average cloud cover in September: 31

The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 29).

[Resources]

Average visibility in September
Belleville, IL

Average visibility in September - Belleville, 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).

[Resources]

Belleville, Illinois, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location