September weather forecast
Bloomington, IL

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Weather in September

September embarks upon the transition from summer to fall in Bloomington, with temperatures starting to cool slightly. The city witnesses a gradual decrease in daylight hours, signaling the forthcoming change of season. Although rain showers become less frequent, they are substantial enough for the foliage to retain its lush green appearance. The cool winds that blow through the city provide an added freshness to the weather. By the end, September has given way to the first signs of fall, with temperatures and foliage starting to change.

Temperature

The arrival of September brings an average high-temperature of a still warm 75.7°F (24.3°C), nearly identical to August's 79.9°F (26.6°C). September nights are marked by an average low-temperature of 57.2°F (14°C).

Humidity

In September, the average relative humidity in Bloomington is 77%.

Rainfall

In September, in Bloomington, the rain falls for 12.2 days. Throughout September, 1.5" (38mm) of precipitation is accumulated. In Bloomington, during the entire year, the rain falls for 140.6 days and collects up to 22.44" (570mm) of precipitation.

Snowfall

May through September are months without snowfall in Bloomington.

Daylight

The average length of the day in September in Bloomington is 12h and 27min.
On the first day of September, sunrise is at 6:24 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm CDT.

Sunshine

In Bloomington, the average sunshine in September is 8.8h.

UV index

In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum UV index of 5 during September translates into these guidelines:
Exercise prevention - Protecting skin and eyes from harm is required. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Bloomington in September?

The high-temperature, in September, in Bloomington, is 75.7°F (24.3°C), while the low-temperature averages to 57.2°F (14°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which factors the actual air temperature with the relative humidity, in July is appraised at 86°F (30°C).

What is the average humidity in September in Bloomington?

In September, the average relative humidity is 77%.

How much does it rain in Bloomington in September?

In Bloomington, Illinois, in September, it is raining for 12.2 days, with typically 1.5" (38mm) of accumulated precipitation.

When it does not snow in Bloomington?

May through September are months without snowfall in Bloomington, Illinois.

Does it snow in Bloomington in September?

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

How many hours of daylight does Bloomington have in September?

In Bloomington, Illinois, the average day length in September is 12h and 27min.

When is the sunrise / sunset in September in Bloomington?

On the first day of September in Bloomington, sunrise is at 6:24 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm CDT.

How long on average sun shines in September in Bloomington?

In September, the average sunshine duration in Bloomington is 8.8h.

What is the UV index reading in September in Bloomington?

In Bloomington, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health risk 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
Bloomington, IL

Average temperature in September - Bloomington, IL
  • Average high temperature in September: 75.7°F

The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is January (30.7°F).

  • Average low temperature in September: 57.2°F

The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure in September
Bloomington, IL

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

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Bloomington, IL

Average wind speed in September - Bloomington, IL
  • Average wind speed in September: 7.8mph

The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest month (with the lowest average wind speed) is August (6.6mph).

Average humidity in September
Bloomington, IL

Average humidity in September - Bloomington, IL
  • Average humidity in September: 77%

The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Bloomington, IL

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

The wettest month (with the highest rainfall) is May (2.99").
The driest month (with the least rainfall) is January (1.18").

Average rainfall days in September
Bloomington, IL

Average rainfall days in September - Bloomington, IL
  • Average rainfall days in September: 12.2 days

The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is February (5.3 days).

Average snowfall in September
Bloomington, IL

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

The month with the highest snowfall is January (2.44").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Bloomington, IL

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

The month with the highest number of snowfall days is January (11.5 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
Bloomington, IL

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

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is June (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).

Average sunshine days in September
Bloomington, IL

Average sunshine days in September - Bloomington, IL
  • Average sunshine days in September: 15 days

The month with the most sunshine days is November (18.4 days).
The month with the least sunshine days is July (9.7 days).

Average UV index in September
Bloomington, IL

Average UV index in September - Bloomington, 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
Bloomington, IL

Average cloud cover in September - Bloomington, IL
  • 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 September (Cloud cover 33).

Average visibility in September
Bloomington, IL

Average visibility in September - Bloomington, IL
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).

Bloomington, Illinois, USA

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