September weather forecastFrederick, IL
September
Weather in September
The first month of the autumn, September, is still a warm month in Frederick, Illinois, with an average temperature ranging between min 58.5°F (14.7°C) and max 77.9°F (25.5°C).Temperature
The arrival of September brings an average high-temperature of a still warm 77.9°F (25.5°C), nearly identical to August's 83.1°F (28.4°C). Frederick's average low-temperature is measured at a refreshing 58.5°F (14.7°C) during September.Humidity
In September, the average relative humidity is 74%.Rainfall
In Frederick, during September, the rain falls for 10.5 days and regularly aggregates up to 2.28" (58mm) of precipitation. Throughout the year, there are 142.2 rainfall days, and 27.95" (710mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall in Frederick.Daylight
In September, the average length of the day is 12h and 26min.On the first day of September, sunrise is at 6:30 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm CDT.
Sunshine
In September, the average sunshine in Frederick is 9.4h.UV index
In Frederick, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: An average maximum UV index of 5 in September leads to these recommendations:
Make use of precautions - It is urged to ward off sun damage. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Frederick, IL
- Average high temperature in September: 77.9°F
The warmest month (with the highest average high temperature) is July (83.3°F).
The month with the lowest average high temperature is January (32.7°F).
- Average low temperature in September: 58.5°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in September
Frederick, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Frederick, IL
- Average wind speed in September: 7.1mph
The windiest months (with the highest average wind speed) are January, February and April (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in September
Frederick, IL
- Average humidity in September: 74%
The month with the highest relative humidity is July (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Frederick, IL
- Average rainfall in September: 2.28"
The wettest month (with the highest rainfall) is May (3.62").
The driest month (with the least rainfall) is December (1.61").
Average rainfall days in September
Frederick, IL
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (6.8 days).
Average snowfall in September
Frederick, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.21").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Frederick, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.1 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
Frederick, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 9h and 24min
The months with the most sunshine are June and July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Frederick, IL
- Average sunshine days in September: 18.2 days
The month with the most sunshine days is October (18.7 days).
The month with the least sunshine days is May (10.9 days).
Average UV index in September
Frederick, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Frederick, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July, August and September (Cloud cover 30).
Average visibility in September
Frederick, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, September, October, November and December (6mi).
The month with the lowest visibility is August (5mi).
