September weather forecastRio, IL
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Rio, Illinois, with temperature in the range of an average high of 75.6°F (24.2°C) and an average low of 56.3°F (13.5°C).Temperature
September's average high-temperature is a still moderately hot 75.6°F (24.2°C), maintaining a close comparison with August's 80.6°F (27°C). Rio witnesses an average low-temperature of 56.3°F (13.5°C) throughout the month of September.Humidity
In Rio, the average relative humidity in September is 76%.Rainfall
In September, the rain falls for 8.7 days. Throughout September, 1.02" (26mm) of precipitation is accumulated. Throughout the year, there are 109.9 rainfall days, and 11.14" (283mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:28 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:44 pm CDT.
Sunshine
In September, the average sunshine is 9.2h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.Note: In September, a regular UV index of 4 translates into these guidelines:
Be vigilant - Suggestions to stave off sun damage are provided. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Rio, IL
- Average high temperature in September: 75.6°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (29.5°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).
Average pressure in September
Rio, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Rio, IL
- Average wind speed in September: 7.9mph
The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).
Average humidity in September
Rio, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Rio, IL
- Average rainfall in September: 1.02"
The wettest month (with the highest rainfall) is May (1.65").
The driest months (with the least rainfall) are January and December (0.47").
Average rainfall days in September
Rio, IL
- Average rainfall days in September: 8.7 days
The month with the highest number of rainy days is May (15.2 days).
The month with the least rainy days is February (3.9 days).
Average snowfall in September
Rio, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.38").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Rio, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.8 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
Rio, IL
- Average daylight in September: 12h and 30min
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 18min).
- Average sunshine in September: 9h and 12min
The month with the most sunshine is June (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Rio, IL
- Average sunshine days in September: 18.4 days
The month with the most sunshine days is December (21.6 days).
The month with the least sunshine days is June (12.4 days).
Average UV index in September
Rio, 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
Rio, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in September
Rio, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
