September weather forecastAllerton, IL
September
Weather in September
The first month of the autumn, September, is still a warm month in Allerton, Illinois, with an average temperature fluctuating between 58.5°F (14.7°C) and 77°F (25°C).Temperature
The onset of September manifests an average high-temperature of a still warm 77°F (25°C), demonstrating a minor variation from the preceding month. During September nights, Allerton witnesses a consistent average temperature of 58.5°F (14.7°C).Humidity
In September, the average relative humidity is 76%.Rainfall
In Allerton, during September, the rain falls for 10.1 days and regularly aggregates up to 0.87" (22mm) of precipitation. Throughout the year, there are 132 rainfall days, and 15.94" (405mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 26min.On the first day of September, sunrise is at 6:20 am and sunset at 7:22 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:35 pm CDT.
Sunshine
In Allerton, the average sunshine in September is 9.1h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: A maximum high UV index of 5 in September translates into the following recommendations:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Allerton, IL
- Average high temperature in September: 77°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (33.3°F).
- Average low temperature in September: 58.5°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (21°F).
Average pressure in September
Allerton, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Allerton, IL
- Average wind speed in September: 7.2mph
The windiest month (with the highest average wind speed) is January (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in September
Allerton, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Allerton, IL
- Average rainfall in September: 0.87"
The wettest month (with the highest rainfall) is April (1.97").
The driest month (with the least rainfall) is February (0.83").
Average rainfall days in September
Allerton, IL
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is July (15.7 days).
The month with the least rainy days is February (6 days).
Average snowfall in September
Allerton, IL
- Average snowfall in September: 0"
The month with the highest snowfall is December (1.26").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Allerton, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8 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
Allerton, 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 6min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Allerton, IL
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is November (19.8 days).
The month with the least sunshine days is July (11.1 days).
Average UV index in September
Allerton, 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
Allerton, IL
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is June (Cloud cover 30).
Average visibility in September
Allerton, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
