September weather forecastFreeport, IL
September
Weather in September
In September, Freeport experiences the onset of autumn, a season celebrated for its vibrant foliage and pleasant weather. The temperatures begin to decline, and the city transitions from the intense heat of summer to more moderate conditions. As leaves begin to change color, parks and forests turn into photographic hubs. The arrival of harvest season brings an atmosphere of prosperity. The natural scenery coupled with the cultural enrichment make September a delightful month.Temperature
In Freeport, the average high-temperature in September slightly decreases from a moderately hot 78.3°F (25.7°C) in August to a pleasant 72.7°F (22.6°C). In the month of September, Freeport records a consistent average low-temperature of 54°F (12.2°C).Humidity
In Freeport, the average relative humidity in September is 80%.Rainfall
In Freeport, in September, it is raining for 11.3 days, with typically 1.46" (37mm) of accumulated precipitation. Throughout the year, there are 138 rainfall days, and 19.69" (500mm) of precipitation is accumulated.Snowfall
In Freeport, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:24 am and sunset at 7:31 pm. On the last day of September, sunrise is at 6:55 am and sunset at 6:41 pm CDT.
Sunshine
The average sunshine in September is 8.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the average person.Note: A maximum daily UV index of 4 during September morphs into the following directions:
Heed the precautions - It is counselled to guard against solar damage. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Freeport, IL
- Average high temperature in September: 72.7°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (25.2°F).
- Average low temperature in September: 54°F
The month with the highest average low temperature is July (62.8°F).
The coldest month (with the lowest average low temperature) is January (13.1°F).
Average pressure in September
Freeport, 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
Freeport, IL
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is April (10.3mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Freeport, IL
- Average humidity in September: 80%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall in September
Freeport, IL
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is June (2.87").
The driest month (with the least rainfall) is December (0.83").
Average rainfall days in September
Freeport, IL
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (4.9 days).
Average snowfall in September
Freeport, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.99").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Freeport, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.3 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
Freeport, 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 6min).
- Average sunshine in September: 8h and 54min
The months with the most sunshine are July and August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Freeport, IL
- Average sunshine days in September: 16.9 days
The month with the most sunshine days is November (17.7 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in September
Freeport, IL
- Average UV index in September: 4
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Freeport, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in September
Freeport, IL
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, February, July and August (5mi).
