Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
A mild shift in the average high-temperature occurs in September, reducing from a moderately hot 78.6°F (25.9°C) in August to an agreeable 73°F (22.8°C). Downers Grove reports an average nighttime low-temperature of 54.3°F (12.4°C) in September.Humidity
In Downers Grove, the average relative humidity in September is 79%.Rainfall
In Downers Grove, in September, it is raining for 11.4 days, with typically 2.52" (64mm) of accumulated precipitation. Throughout the year, there are 142.5 rainfall days, and 28.27" (718mm) of precipitation is accumulated.Snowfall
In Downers Grove, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:31 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:01 am and sunset at 6:47 pm CDT.
Sunshine
In Downers Grove, the average sunshine in September is 9.1h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: A typical high UV index of 4 in September suggests the following recommendations:
Take precautions - Protection against skin and eye damage is obliged. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Downers Grove have in September?
What is the UV index reading in September?
Average temperature in September
Downers Grove, IA
- Average high temperature in September: 73°F
The warmest month (with the highest average high temperature) is July (80.1°F).
The month with the lowest average high temperature is January (25.2°F).
- Average low temperature in September: 54.3°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.3°F).
Average pressure in September
Downers Grove, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Downers Grove, IA
- Average wind speed in September: 8mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.9mph).
Average humidity in September
Downers Grove, IA
- Average humidity in September: 79%
The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Downers Grove, IA
- Average rainfall in September: 2.52"
The wettest month (with the highest rainfall) is May (4.25").
The driest months (with the least rainfall) are January and February (1.26").
Average rainfall days in September
Downers Grove, IA
- Average rainfall days in September: 11.4 days
The month with the highest number of rainy days is May (18.6 days).
The month with the least rainy days is January (5.2 days).
Average snowfall in September
Downers Grove, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.04").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Downers Grove, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.1 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
Downers Grove, IA
- 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 months with the most sunshine are July and August (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Downers Grove, IA
- Average sunshine days in September: 17 days
The month with the most sunshine days is September (17 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in September
Downers Grove, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Downers Grove, IA
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Downers Grove, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January and July (5mi).
Downers Grove, Iowa, USA
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