September weather forecastFrankfort, IL
September
Weather in September
The first month of the autumn, September, is still a warm month in Frankfort, Illinois, with an average temperature fluctuating between 57.9°F (14.4°C) and 73.9°F (23.3°C).Temperature
The beginning of September brings a minor change in the average high-temperature, shifting from 79.9°F (26.6°C) in August to a still warm 73.9°F (23.3°C). Frankfort throughout September, experiences an average nighttime temperature of 57.9°F (14.4°C).Humidity
The average relative humidity in September is 76%.Rainfall
In Frankfort, during September, the rain falls for 10.4 days and regularly aggregates up to 0.98" (25mm) of precipitation. In Frankfort, during the entire year, the rain falls for 111.8 days and collects up to 11.18" (284mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September in Frankfort is 12h and 28min.On the first day of September in Frankfort, sunrise is at 6:18 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:34 pm CDT.
Sunshine
The average sunshine in September is 8.8h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: In September, the maximum UV index of 4 suggests these recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Frankfort, IL
- Average high temperature in September: 73.9°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in September: 57.9°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.7°F).
Average pressure in September
Frankfort, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Frankfort, IL
- Average wind speed in September: 7.2mph
The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in September
Frankfort, IL
- Average humidity in September: 76%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Frankfort, IL
- Average rainfall in September: 0.98"
The wettest month (with the highest rainfall) is May (1.54").
The driest months (with the least rainfall) are January, February and December (0.55").
Average rainfall days in September
Frankfort, IL
- Average rainfall days in September: 10.4 days
The month with the highest number of rainy days is July (14.1 days).
The month with the least rainy days is February (4.1 days).
Average snowfall in September
Frankfort, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.3").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Frankfort, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.3 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
Frankfort, IL
- Average daylight in September: 12h and 30min
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 48min
The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Frankfort, IL
- Average sunshine days in September: 17 days
The month with the most sunshine days is November (20.7 days).
The month with the least sunshine days is June (13.1 days).
Average UV index in September
Frankfort, IL
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Frankfort, 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 August (Cloud cover 30).
Average visibility in September
Frankfort, 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).
