September weather forecast
Berwyn, IL

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Weather in September

September signals the advent of autumn in Berwyn, with temperatures starting to slide down from their summer highs. The temperature in this month is less intense compared to August, but September maintains a moderately warm climate. Interestingly, September records the highest wind gusts speed at 12.4mph (20km/h). The transition from summer to fall brings on a combination of warm days and relatively cooler nights, setting the perfect stage for night-time activities. The departure of the intense summer heat combined with the arrival of a gentle breeze makes September a delightful month in Berwyn.

Temperature

Berwyn's September weather features a light decline in high-temperatures, reducing from a moderately hot 79.3°F (26.3°C) in August to a pleasant 72.9°F (22.7°C). During September nights, Berwyn records an average temperature of 59.5°F (15.3°C).

Humidity

The average relative humidity in September is 74%.

Rainfall

In Berwyn, Illinois, during September, the rain falls for 7.5 days and regularly aggregates up to 0.51" (13mm) of precipitation. Throughout the year, there are 92 rainfall days, and 7.4" (188mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall.

Daylight

In Berwyn, the average length of the day in September is 12h and 28min.
On the first day of September, sunrise is at 6:17 am and sunset at 7:24 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:34 pm CDT.

Sunshine

The average sunshine in September is 9.1h.

UV index

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.
Note: The maximum daily UV index of 4 during September translates into the following directions:
Make use of precautions - It is urged to ward off sun damage. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
Updated: Aug 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

September temperatures vary between a high-temperature of 72.9°F (22.7°C) and a low-temperature of 59.5°F (15.3°C).

What is the average humidity in September?

The average relative humidity in September is 74%.

How much does it rain in Berwyn in September?

In Berwyn, in September, during 7.5 rainfall days, 0.51" (13mm) of precipitation is typically accumulated.

When it does not snow?

In Berwyn, snow does not fall in May through September.

Does it snow in September?

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

What is the average length of the day in September?

In September, the average day length 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 7:24 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:34 pm CDT.

How long on average sun shines in September?

The average sunshine duration in September is 9.1h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium hazard to health 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
Berwyn, IL

Average temperature in September - Berwyn, IL
  • Average high temperature in September: 72.9°F

The warmest month (with the highest average high temperature) is July (80.4°F).
The month with the lowest average high temperature is January (29.1°F).

  • Average low temperature in September: 59.5°F

The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (19.2°F).

Average pressure in September
Berwyn, IL

Average pressure in September - Berwyn, 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
Berwyn, IL

Average wind speed in September - Berwyn, IL
  • Average wind speed in September: 8.1mph

The windiest month (with the highest average wind speed) is January (10.9mph).
The calmest month (with the lowest average wind speed) is August (6.8mph).

Average humidity in September
Berwyn, IL

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

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).

Average rainfall in September
Berwyn, IL

Average rainfall in September - Berwyn, IL
  • Average rainfall in September: 0.51"

The wettest month (with the highest rainfall) is May (1.1").
The driest months (with the least rainfall) are February, March, November and December (0.39").

Average rainfall days in September
Berwyn, IL

Average rainfall days in September - Berwyn, IL
  • Average rainfall days in September: 7.5 days

The month with the highest number of rainy days is June (11.7 days).
The month with the least rainy days is January (3.1 days).

Average snowfall in September
Berwyn, IL

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

The month with the highest snowfall is February (1.38").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Berwyn, IL

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

The month with the highest number of snowfall days is February (7.3 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
Berwyn, IL

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

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

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).

Average sunshine days in September
Berwyn, IL

Average sunshine days in September - Berwyn, IL
  • Average sunshine days in September: 19.9 days

The month with the most sunshine days is December (23.7 days).
The month with the least sunshine days is June (14.3 days).

Average UV index in September
Berwyn, IL

Average UV index in September - Berwyn, IL
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in September
Berwyn, IL

Average cloud cover in September - Berwyn, IL
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 27).

Average visibility in September
Berwyn, IL

Average visibility in September - Berwyn, 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).

Berwyn, Illinois, USA

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