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
In September, the average high-temperature marginally drops from a warm 78.4°F (25.8°C) in August to a pleasant 72.9°F (22.7°C). Throughout September, the average low-temperature dips to a cool 54.5°F (12.5°C).Humidity
In September, the average relative humidity is 79%.Rainfall
In Shannon, Illinois, in September, it is raining for 10.7 days, with typically 1.5" (38mm) of accumulated precipitation. Throughout the year, there are 130.8 rainfall days, and 17.95" (456mm) of precipitation is accumulated.Snowfall
In Shannon, Illinois, snow does not fall in May through September.Daylight
In Shannon, the average length of the day in September is 12h and 28min.On the first day of September in Shannon, sunrise is at 6:25 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:41 pm CDT.
Sunshine
In Shannon, Illinois, the average sunshine in September is 9h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: A daily high UV index of 4 in September leads to these guidelines:
Undertake precautions - It is suggested to shield oneself from sunburn. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Frequently asked questions
What is the usual temperature for Shannon in September?
What is the average humidity in September in Shannon?
How much does it rain in Shannon in September?
When it does not snow in Shannon?
Does it snow in Shannon in September?
How many hours of daylight does Shannon have in September?
When are sunrise and sunset in September in Shannon?
How many hours of sunshine does Shannon have in September?
What is the UV index intensity in September in Shannon?
Average temperature in September
Shannon, IL
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (25.9°F).
- Average low temperature in September: 54.5°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 (13.5°F).
Average pressure in September
Shannon, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Shannon, IL
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Shannon, IL
- Average humidity in September: 79%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall in September
Shannon, IL
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is May (2.76").
The driest months (with the least rainfall) are January and February (0.71").
Average rainfall days in September
Shannon, IL
- Average rainfall days in September: 10.7 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Shannon, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Shannon, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.2 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
Shannon, 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 0min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Shannon, IL
- Average sunshine days in September: 17.8 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (10 days).
Average UV index in September
Shannon, IL
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Shannon, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in September
Shannon, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Shannon, Illinois, USA
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