September weather forecastWest Vienna, IL
September
Weather in September
September, the first month of the autumn in West Vienna, is also a moderately hot month, with an average temperature ranging between min 60.6°F (15.9°C) and max 81.1°F (27.3°C).Temperature
With the onset of September, West Vienna's average high-temperature slightly adjusts, moderately receding from August's hot 86.5°F (30.3°C) to a warm 81.1°F (27.3°C). During the September nights, an average temperature of 60.6°F (15.9°C) is observed.Heat index
The average heat index in September is computed to be a tropical 86°F (30°C). If one persists in activity during exposure, it could induce weariness and subsequently, heat cramps.Heat index guidelines indicate values are for light wind scenarios and shaded regions. The heat index could experience an increase of 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'real feel', provides an understanding of perceived warmth by combining temperature and relative humidity. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. In the direct sunlight, the weather's impact can be amplified, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
Humidity
The average relative humidity in September in West Vienna is 73%.Rainfall
The month with the least rainfall in West Vienna is September, when the rain falls for 8.3 days and typically collects 0.47" (12mm) of precipitation.Snowfall
In West Vienna, snow does not fall in April through October.Daylight
In September, the average length of the day in West Vienna is 12h and 25min.On the first day of September in West Vienna, Illinois, sunrise is at 6:26 am and sunset at 7:24 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:40 pm CDT.
Sunshine
In West Vienna, the average sunshine in September is 9.4h.UV index
In September, the average daily maximum UV index in West Vienna is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: A typical high UV index of 5 in September suggests the following recommendations:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
West Vienna, IL
- Average high temperature in September: 81.1°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (40.1°F).
- Average low temperature in September: 60.6°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (27°F).
Average pressure in September
West Vienna, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
West Vienna, IL
- Average wind speed in September: 6.3mph
The windiest months (with the highest average wind speed) are January and February (9mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in September
West Vienna, IL
- Average humidity in September: 73%
The months with the highest relative humidity are March and May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
West Vienna, IL
- Average rainfall in September: 0.47"
The wettest month (with the highest rainfall) is June (1.5").
The driest month (with the least rainfall) is September (0.47").
Average rainfall days in September
West Vienna, IL
- Average rainfall days in September: 8.3 days
The month with the highest number of rainy days is July (13.1 days).
The months with the least rainy days are January, February and December (7.3 days).
Average snowfall in September
West Vienna, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.67").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
West Vienna, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (3.3 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
West Vienna, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 9h and 24min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 36min).
Average sunshine days in September
West Vienna, IL
- Average sunshine days in September: 19.1 days
The month with the most sunshine days is October (21.5 days).
The month with the least sunshine days is June (14.8 days).
Average UV index in September
West Vienna, IL
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in September
West Vienna, IL
- Average cloud cover in September: 28
The months with the most cloud cover are January and February (Cloud cover 51).
The month with the least cloud cover is September (Cloud cover 28).
Average visibility in September
West Vienna, 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).
