September weather forecastUllin, IL
September
Weather in September
September, the first month of the autumn in Ullin, is still a warm month, with an average temperature ranging between min 60.6°F (15.9°C) and max 81°F (27.2°C).Temperature
September brings a slight decrease in the average high-temperature, shifting from a tropical 86.5°F (30.3°C) in August to a warm 81°F (27.2°C). In the month of September, the nighttime temperature in Ullin, Illinois, dips to a steady average of 60.6°F (15.9°C).Heat index
September's mean heat index is computed to be 84.2°F (29°C). Persistent activity under exposure might lead to a feeling of weariness, with subsequent heat cramps.Remember that heat index calculations are made for conditions in the shade with light wind. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is a measure of how hot it feels when the actual air humidity is factored in. The effect is personal, with varied weather perceptions among individuals due to differences in body mass, stature, and physical activity. Direct exposure to the sun's rays can enhance the felt temperature, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Young ones often do not realize the necessity to rest and replenish their fluids. Thirst is a delayed indication of dehydration - keeping hydrated, particularly in prolonged physical activity, is crucial.
Humidity
In Ullin, Illinois, the average relative humidity in September is 73%.Rainfall
The month with the least rainfall is September, when the rain falls for 10.8 days and typically collects 1.3" (33mm) of precipitation.Snowfall
In Ullin, snow does not fall in May through September.Daylight
In September, the average length of the day in Ullin is 12h and 25min.On the first day of September in Ullin, sunrise is at 6:27 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:40 pm CDT.
Sunshine
The average sunshine in September is 9.5h.UV index
In September, the average daily maximum UV index in Ullin is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: The average daily UV index of 5 in September transforms into the following instructions:
Take precautions - Protection against sun damage is advised. Around midday, solar radiation is most harmful; hence, exposure should be limited. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Ullin, IL
- Average high temperature in September: 81°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in September: 60.6°F
The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (26.8°F).
Average pressure in September
Ullin, IL
- Average pressure in September: 30.02"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
Ullin, IL
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is January (9mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).
Average humidity in September
Ullin, IL
- Average humidity in September: 73%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Ullin, IL
- Average rainfall in September: 1.3"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is September (1.3").
Average rainfall days in September
Ullin, IL
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is July (15.9 days).
The month with the least rainy days is January (8.4 days).
Average snowfall in September
Ullin, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.89").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Ullin, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.6 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
Ullin, 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 30min
The month with the most sunshine is 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
Ullin, IL
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is October (21 days).
The month with the least sunshine days is July (12.8 days).
Average UV index in September
Ullin, 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
Ullin, IL
- Average cloud cover in September: 28
The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is September (Cloud cover 28).
Average visibility in September
Ullin, 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).
