September weather forecastRiver Grove, IL
September
Weather in September
September, the first month of the autumn in River Grove, is still a pleasant month, with an average temperature fluctuating between 72.1°F (22.3°C) and 60.4°F (15.8°C).Temperature
Start of September brings a slight shift in the average high-temperature, dipping a bit from August's warm 79.3°F (26.3°C) to a pleasant 72.1°F (22.3°C). Throughout the month of September, River Grove observes an average nighttime temperature of 60.4°F (15.8°C).Humidity
The average relative humidity in September is 74%.Rainfall
In River Grove, in September, it is raining for 14.5 days, with typically 2.72" (69mm) of accumulated precipitation. Throughout the year, in River Grove, there are 157.8 rainfall days, and 33.7" (856mm) of precipitation is accumulated.Snowfall
In River Grove, snow does not fall in June through September.Daylight
In River Grove, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:17 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:34 pm CDT.
Sunshine
The average sunshine in September is 9h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the average person.Note: A daily high UV index of 4 in September leads to these guidelines:
Exercise care. People with light skin might get burns in fewer than 30 minutes. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
River Grove, IL
- Average high temperature in September: 72.1°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (28.9°F).
- Average low temperature in September: 60.4°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (19.4°F).
Average pressure in September
River Grove, 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
River Grove, IL
- Average wind speed in September: 8.3mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in September
River Grove, IL
- Average humidity in September: 74%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
River Grove, IL
- Average rainfall in September: 2.72"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is December (1.57").
Average rainfall days in September
River Grove, IL
- Average rainfall days in September: 14.5 days
The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is February (5.1 days).
Average snowfall in September
River Grove, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.69").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
River Grove, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
River Grove, IL
- Average daylight in September: 12h and 30min
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 0min
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 42min).
Average sunshine days in September
River Grove, IL
- Average sunshine days in September: 13.4 days
The month with the most sunshine days is December (16.7 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in September
River Grove, 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
River Grove, 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
River Grove, 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).
