September weather forecastProspect Heights, IL
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Prospect Heights, Illinois, with temperature in the range of an average high of 73.2°F (22.9°C) and an average low of 58.8°F (14.9°C).Temperature
September's onset introduces a mild reduction in the average high-temperature, from a warm 79.7°F (26.5°C) in August to a pleasant 73.2°F (22.9°C). In Prospect Heights, the average nighttime temperature during September is a moderate 58.8°F (14.9°C).Humidity
In Prospect Heights, the average relative humidity in September is 74%.Rainfall
In Prospect Heights, in September, it is raining for 13.2 days, with typically 2.24" (57mm) of accumulated precipitation. In Prospect Heights, during the entire year, the rain falls for 153.3 days and collects up to 30.12" (765mm) of precipitation.Snowfall
In Prospect Heights, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 28min.On the first day of September, sunrise is at 6:18 am and sunset at 7:24 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:34 pm CDT.
Sunshine
In Prospect Heights, the average sunshine in September is 8.8h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Prospect Heights, IL
- Average high temperature in September: 73.2°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (28.2°F).
- Average low temperature in September: 58.8°F
The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (18°F).
Average pressure in September
Prospect Heights, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Prospect Heights, IL
- Average wind speed in September: 7.7mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Prospect Heights, IL
- Average humidity in September: 74%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Prospect Heights, IL
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is May (3.9").
The driest month (with the least rainfall) is December (1.46").
Average rainfall days in September
Prospect Heights, IL
- Average rainfall days in September: 13.2 days
The month with the highest number of rainy days is May (18 days).
The month with the least rainy days is February (5.6 days).
Average snowfall in September
Prospect Heights, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.96").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Prospect Heights, 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 June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Prospect Heights, IL
- Average daylight in September: 12h and 30min
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 12min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Prospect Heights, IL
- Average sunshine days in September: 14.1 days
The month with the most sunshine days is November (16.3 days).
The month with the least sunshine days is June (10.7 days).
Average UV index in September
Prospect Heights, IL
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Prospect Heights, IL
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in September
Prospect Heights, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
