September weather forecast
Olympia Fields, IL

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Weather in September

September, the first month of the autumn in Olympia Fields, is also a moderately hot month, with an average temperature fluctuating between 58.3°F (14.6°C) and 73.9°F (23.3°C).

Temperature

As September arrives, Olympia Fields's weather displays a minor decrease in high-temperatures, transitioning from August's 80.1°F (26.7°C) to a still warm 73.9°F (23.3°C). Throughout September, the average low-temperature records at a mild 58.3°F (14.6°C).

Humidity

The average relative humidity in September is 76%.

Rainfall

In September, the rain falls for 13.4 days. Throughout September, 2.48" (63mm) of precipitation is accumulated. In Olympia Fields, during the entire year, the rain falls for 155.6 days and collects up to 31.3" (795mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 28min.
On the first day of the month, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:33 pm CDT.

Sunshine

In September, the average sunshine is 8.8h.

UV index

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: A maximum high UV index of 4 in September translates into the following recommendations:
Put precautions into practice - Guidance to elude sunburn is provided. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Updated: Aug 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

The average high-temperature, in September, in Olympia Fields, is 73.9°F (23.3°C), while the average low-temperature is 58.3°F (14.6°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, in July is estimated at 87.8°F (31°C).

What is the average humidity in September?

The average relative humidity in September is 76%.

How much does it rain in September?

In September, the rain falls for 13.4 days. Throughout September, 2.48" (63mm) of precipitation is accumulated.

When it does not snow in Olympia Fields?

In Olympia Fields, snow does not fall in May through September.

Does it snow in September?

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

What is the average length of the day in September?

In Olympia Fields, the average day length in September is 12h and 28min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:33 pm CDT.

How long on average sun shines in September?

In September, the average sunshine duration is 8.8h.

What is the UV index reading in September?

In Olympia Fields, Illinois, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health risk 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
Olympia Fields, IL

Average temperature in September - Olympia Fields, IL
  • Average high temperature in September: 73.9°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 (29.7°F).

  • Average low temperature in September: 58.3°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure in September
Olympia Fields, IL

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

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Olympia Fields, IL

Average wind speed in September - Olympia Fields, IL
  • Average wind speed in September: 7.3mph

The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).

Average humidity in September
Olympia Fields, IL

Average humidity in September - Olympia Fields, IL
  • Average humidity in September: 76%

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).

Average rainfall in September
Olympia Fields, IL

Average rainfall in September - Olympia Fields, IL
  • Average rainfall in September: 2.48"

The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").

Average rainfall days in September
Olympia Fields, IL

Average rainfall days in September - Olympia Fields, IL
  • Average rainfall days in September: 13.4 days

The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).

Average snowfall in September
Olympia Fields, IL

Average snowfall in September - Olympia Fields, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Olympia Fields, IL

Average snowfall days in September - Olympia Fields, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Olympia Fields, IL

Average daylight in September / Average sunshine in September - Olympia Fields, IL
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).

Average sunshine days in September
Olympia Fields, IL

Average sunshine days in September - Olympia Fields, IL
  • Average sunshine days in September: 14 days

The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).

Average UV index in September
Olympia Fields, IL

Average UV index in September - Olympia Fields, IL
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in September
Olympia Fields, IL

Average cloud cover in September - Olympia Fields, IL
  • Average cloud cover in September: 32

The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in September
Olympia Fields, IL

Average visibility in September - Olympia Fields, IL
  • Average visibility in September: 6mi

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

Olympia Fields, Illinois, USA

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