September weather forecastStreator, IL
September
Weather in September
September, the first month of the autumn in Streator, is still a warm month, with an average temperature fluctuating between 56.5°F (13.6°C) and 75°F (23.9°C).Temperature
The commencement of September brings an average high-temperature of a still moderately hot 75°F (23.9°C), marking an inconsequential divergence from August. During the nights in September, the temperature averages to a moderate 56.5°F (13.6°C).Humidity
The average relative humidity in September is 77%.Rainfall
In Streator, in September, it is raining for 12.1 days, with typically 1.85" (47mm) of accumulated precipitation. Throughout the year, there are 145 rainfall days, and 25.08" (637mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:22 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:38 pm CDT.
Sunshine
In Streator, 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 moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: The daily high UV index of 4 in September translates into this advice:
Put precautions into practice - Ensuring skin and eye safety is a necessity. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Streator, IL
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.5°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (17.8°F).
Average pressure in September
Streator, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Streator, IL
- Average wind speed in September: 7.4mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in September
Streator, IL
- Average humidity in September: 77%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Streator, IL
- Average rainfall in September: 1.85"
The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is December (1.18").
Average rainfall days in September
Streator, IL
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is July (18.1 days).
The month with the least rainy days is February (5.3 days).
Average snowfall in September
Streator, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.27").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Streator, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.8 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
Streator, 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 18min).
- Average sunshine in September: 8h and 54min
The month with the most sunshine is June (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Streator, IL
- Average sunshine days in September: 15.9 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is July (9.2 days).
Average UV index in September
Streator, 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
Streator, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 59).
The months with the least cloud cover are August and September (Cloud cover 32).
Average visibility in September
Streator, 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).





