September weather forecastPeoria, IL

September
Weather in September
September in Peoria, Illinois embodies the emerging fall, with nature painting the town in warm, earthy hues. The marked decrease in high temperatures to 76.1°F (24.5°C) and increase in wind speed introduces the crispness of autumn. This month also witnesses a decrease in the amount of rainfall and daylight hours, heightening the autumn feel. As temperatures drop and humidity levels decline, residents welcome the cooler, refreshing weather, making it a popular time for fall harvest festivities and family picnics.Temperature
With September's advent, Peoria sees an average high-temperature of a still warm 76.1°F (24.5°C), subtly shifted from August's 81.1°F (27.3°C). Peoria observes an average nighttime temperature of 57.2°F (14°C) during September.Humidity
In September, the average relative humidity is 76%.Rainfall
In Peoria, in September, it is raining for 10.5 days, with typically 1.42" (36mm) of accumulated precipitation. Throughout the year, there are 129.2 rainfall days, and 17.24" (438mm) of precipitation is accumulated.Snowfall
In Peoria, Illinois, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 27min.On the first day of September, sunrise is at 6:26 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:41 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: The maximum daily UV index of 5 during September translates into the following directions:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Peoria, IL
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (30.7°F).
- Average low temperature in September: 57.2°F
The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
Peoria, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Peoria, IL
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Peoria, 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 (71%).
Average rainfall in September
Peoria, IL
- Average rainfall in September: 1.42"
The wettest month (with the highest rainfall) is May (2.64").
The driest month (with the least rainfall) is January (0.75").
Average rainfall days in September
Peoria, IL
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (4.6 days).
Average snowfall in September
Peoria, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.36").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Peoria, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9 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
Peoria, 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 18min).
- Average sunshine in September: 9h and 18min
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 0min).
Average sunshine days in September
Peoria, IL
- Average sunshine days in September: 17.9 days
The month with the most sunshine days is November (19.8 days).
The month with the least sunshine days is May (11.3 days).
Average UV index in September
Peoria, 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
Peoria, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 57).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in September
Peoria, 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).





