Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Stepping into September, Iroquois records an average high-temperature of a still moderately hot 75°F (23.9°C), almost consistent with August. During September, an average low-temperature of 56.8°F (13.8°C) is observed.Humidity
The average relative humidity in September is 78%.Rainfall
In Iroquois, in September, during 11.3 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. Throughout the year, there are 140.3 rainfall days, and 17.56" (446mm) of precipitation is accumulated.Snowfall
In Iroquois, snow does not fall in May through October.Daylight
In Iroquois, the average length of the day in September is 12h and 27min.On the first day of the month, sunrise is at 6:17 am and sunset at 7:22 pm. On the last day of September, sunrise is at 6:46 am and sunset at 6:33 pm CDT.
Sunshine
The average sunshine in September is 8.5h.UV index
In Iroquois, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for ordinary individuals.Note: A maximum high daily UV index of 5 during September translates into the following directions:
Make use of precautions - Suggestions to resist sunburn are communicated. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
How many hours of daylight does Iroquois have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Iroquois have in September?
What is the UV index intensity in September?
Average temperature in September
Iroquois, 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 (30.7°F).
- Average low temperature in September: 56.8°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
Iroquois, 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 (29.93"Hg).
Average wind speed in September
Iroquois, IL
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in September
Iroquois, IL
- Average humidity in September: 78%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Iroquois, IL
- Average rainfall in September: 1.1"
The wettest month (with the highest rainfall) is May (2.64").
The driest months (with the least rainfall) are January and February (0.79").
Average rainfall days in September
Iroquois, IL
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is January (4.9 days).
Average snowfall in September
Iroquois, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Iroquois, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.3 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
Iroquois, IL
- Average daylight in September: 12h and 3min
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 3min
The months with the most sunshine are June and July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Iroquois, IL
- Average sunshine days in September: 15.5 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is July (9.4 days).
Average UV index in September
Iroquois, IL
- Average UV index in September: 5
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
Iroquois, IL
- Average cloud cover in September: 34
The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are July, August and September (Cloud cover 34).
Average visibility in September
Iroquois, 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).
Iroquois, Illinois, USA
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