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
As Somonauk transitions from August to September, the average high-temperatures adjust to a still warm 73.8°F (23.2°C), nearly the same as the previous 79°F (26.1°C). Nighttime temperature lowers to an average of 55.4°F (13°C) in September.Humidity
The average relative humidity in September is 79%.Rainfall
In September, the rain falls for 13.8 days. Throughout September, 2.4" (61mm) of precipitation is accumulated. Throughout the year, there are 162.1 rainfall days, and 33.54" (852mm) of precipitation is accumulated.Snowfall
In Somonauk, snow does not fall in May through September.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:21 am and sunset at 7:27 pm. On the last day of September, sunrise is at 6:51 am and sunset at 6:37 pm CDT.
Sunshine
In September, the average sunshine is 8.7h.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 unsafe exposure to UV radiation for the average person.Note: In September, a regular UV index of 4 translates into these guidelines:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Somonauk in September?
What is the average humidity in September?
How much does it rain in Somonauk in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Somonauk have in September?
What time are sunrise and sunset in September?
How long on average sun shines in September in Somonauk?
How high is the UV index in September?
Average temperature in September
Somonauk, IL
- Average high temperature in September: 73.8°F
The warmest month (with the highest average high temperature) is July (80.6°F).
The month with the lowest average high temperature is January (27.5°F).
- Average low temperature in September: 55.4°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 (15.6°F).
Average pressure in September
Somonauk, 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 (29.92"Hg).
Average wind speed in September
Somonauk, IL
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is April (9.9mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in September
Somonauk, IL
- Average humidity in September: 79%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Somonauk, IL
- Average rainfall in September: 2.4"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is January (1.69").
Average rainfall days in September
Somonauk, IL
- Average rainfall days in September: 13.8 days
The months with the highest number of rainy days are June and July (19.3 days).
The month with the least rainy days is January (5.5 days).
Average snowfall in September
Somonauk, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.61").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Somonauk, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Somonauk, IL
- Average daylight in September: 12h and 3min
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 12min).
- Average sunshine in September: 8h and 4min
The months with the most sunshine are June, July and August (Average sunshine: 9h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Somonauk, IL
- Average sunshine days in September: 13.5 days
The month with the most sunshine days is November (17 days).
The month with the least sunshine days is July (8.2 days).
Average UV index in September
Somonauk, IL
- Average UV index in September: 4
The months with the highest UV index are June and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Somonauk, IL
- Average cloud cover in September: 34
The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 34).
Average visibility in September
Somonauk, IL
- Average visibility in September: 5mi
The months with the highest visibility are March, April, May, June, October, November and December (6mi).
The months with the lowest visibility are January, February, July, August and September (5mi).
Somonauk, Illinois, USA
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