September weather forecastRiverside, IL
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Riverside, Illinois, with an average temperature fluctuating between 59.5°F (15.3°C) and 72.9°F (22.7°C).Temperature
In September, the meteorological conditions change slightly, with the average high-temperature moving from a moderately hot 79.3°F (26.3°C) in August to an agreeable 72.9°F (22.7°C). Throughout the nights in September, an average low-temperature of 59.5°F (15.3°C) is noted.Humidity
In Riverside, the average relative humidity in September is 74%.Rainfall
In September, in Riverside, the rain falls for 7.5 days. Throughout September, 0.51" (13mm) of precipitation is accumulated. Throughout the year, in Riverside, Illinois, there are 92 rainfall days, and 7.4" (188mm) of precipitation is accumulated.Snowfall
In Riverside, Illinois, 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 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 in Riverside, Illinois, is 9.1h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.Note: The average daily UV index of 4 in September transforms into the following instructions:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Avoiding the Sun during its peak radiation time around midday is a healthy practice. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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 6min
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
Riverside, 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
Riverside, 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
Riverside, 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
Riverside, 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).
