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
In September, the meteorological conditions change slightly, with the average high-temperature moving from a moderately hot 78.6°F (25.9°C) in August to an agreeable 72.3°F (22.4°C). The average low-temperature of 57°F (13.9°C) is witnessed during September.Humidity
In September, the average relative humidity is 77%.Rainfall
In Grayslake, during September, the rain falls for 11.9 days and regularly aggregates up to 1.57" (40mm) of precipitation. Throughout the year, in Grayslake, there are 142.3 rainfall days, and 21.97" (558mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day in Grayslake is 12h and 28min.On the first day of the month, sunrise is at 6:18 am and sunset at 7:25 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:34 pm CDT.
Sunshine
In Grayslake, 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 threat to health from exposure to the Sun's UV rays for average individuals.Note: The maximum daily UV index of 4 in September interprets into the following recommendations:
Guard yourself - Precautionary measures against sun damage are advocated. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Grayslake have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Grayslake have in September?
What is the UV index reading in September?
Average temperature in September
Grayslake, IL
- Average high temperature in September: 72.3°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (27.5°F).
- Average low temperature in September: 57°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 (16.5°F).
Average pressure in September
Grayslake, IL
- Average pressure in September: 30.03"Hg
The months with the highest atmospheric pressure are January and February (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Grayslake, IL
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in September
Grayslake, IL
- Average humidity in September: 77%
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Grayslake, IL
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is April (2.72").
The driest month (with the least rainfall) is December (0.98").
Average rainfall days in September
Grayslake, IL
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is July (17.5 days).
The month with the least rainy days is February (5 days).
Average snowfall in September
Grayslake, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.58").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Grayslake, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (13.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Grayslake, IL
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Grayslake, IL
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is May (10.8 days).
Average UV index in September
Grayslake, IL
- Average UV index in September: 4
The months with the highest UV index are July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Grayslake, IL
- Average cloud cover in September: 30
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 30).
Average visibility in September
Grayslake, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Grayslake, Illinois, USA
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