September weather forecastStillman Valley, IL
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Stillman Valley, Illinois, with an average temperature fluctuating between 54.3°F (12.4°C) and 72.7°F (22.6°C).Temperature
A subtle shift in Stillman Valley's weather is observed as August turns into September, with the average high temperature reducing from a moderately hot 78.1°F (25.6°C) to an agreeable 72.7°F (22.6°C). An average low-temperature of 54.3°F (12.4°C) marks the nights throughout September.Humidity
In Stillman Valley, the average relative humidity in September is 80%.Rainfall
In Stillman Valley, in September, it is raining for 7.7 days, with typically 0.63" (16mm) of accumulated precipitation. In Stillman Valley, during the entire year, the rain falls for 100.6 days and collects up to 7.99" (203mm) of precipitation.Snowfall
May through September are months without snowfall in Stillman Valley.Daylight
In Stillman Valley, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:23 am and sunset at 7:29 pm. On the last day of September, in Stillman Valley, Illinois, sunrise is at 6:53 am and sunset at 6:39 pm CDT.
Sunshine
In September, the average sunshine in Stillman Valley is 8.7h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: In September, a daily UV index of 4 turns into the following recommendations:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Stillman Valley, IL
- Average high temperature in September: 72.7°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 (26.2°F).
- Average low temperature in September: 54.3°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (14°F).
Average pressure in September
Stillman Valley, 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
Stillman Valley, IL
- Average wind speed in September: 7.4mph
The windiest month (with the highest average wind speed) is April (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).
Average humidity in September
Stillman Valley, IL
- Average humidity in September: 80%
The month with the highest relative humidity is January (86%).
The months with the lowest relative humidity are April and October (75%).
Average rainfall in September
Stillman Valley, IL
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is May (1.18").
The driest months (with the least rainfall) are January and February (0.35").
Average rainfall days in September
Stillman Valley, IL
- Average rainfall days in September: 7.7 days
The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is January (3.2 days).
Average snowfall in September
Stillman Valley, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.42").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Stillman Valley, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.1 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
Stillman Valley, 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: 8h and 42min
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
Stillman Valley, IL
- Average sunshine days in September: 20 days
The month with the most sunshine days is December (22.6 days).
The month with the least sunshine days is June (12.8 days).
Average UV index in September
Stillman Valley, 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
Stillman Valley, IL
- Average cloud cover in September: 33
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is September (Cloud cover 33).
Average visibility in September
Stillman Valley, 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).
