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
The shift into September finds Undercliff at an average high-temperature of a still warm 75°F (23.9°C), closely comparable to August's conditions. During the month of September, the nighttime temperature falls to an average of 56.5°F (13.6°C).Humidity
In Undercliff, Illinois, the average relative humidity in September is 77%.Rainfall
In Undercliff, during September, the rain falls for 11.7 days and regularly aggregates up to 2.24" (57mm) of precipitation. In Undercliff, during the entire year, the rain falls for 151.3 days and collects up to 30.16" (766mm) of precipitation.Snowfall
In Undercliff, Illinois, snow does not fall in May through September.Daylight
In September, the average length of the day is 12h and 28min.On the first day of September in Undercliff, Illinois, sunrise is at 6:24 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:40 pm CDT.
Sunshine
In Undercliff, the average sunshine in September is 9h.UV index
In September, the average daily maximum UV index in Undercliff 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: The UV index of 4 during September translates into the following guidance:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Undercliff?
What is the average humidity in September in Undercliff?
How many days does it rain in September in Undercliff?
When it does not snow in Undercliff?
Does it snow in Undercliff in September?
What is the average length of the day in September in Undercliff?
When are sunrise and sunset in September in Undercliff?
How many hours of sunshine does Undercliff have in September?
How high is the UV index in September in Undercliff?
Average temperature in September
Undercliff, 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 (29.3°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).
Average pressure in September
Undercliff, 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 (29.91"Hg).
Average wind speed in September
Undercliff, 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
Undercliff, 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
Undercliff, IL
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is May (4.41").
The driest months (with the least rainfall) are January and December (1.57").
Average rainfall days in September
Undercliff, IL
- Average rainfall days in September: 11.7 days
The month with the highest number of rainy days is May (18.4 days).
The month with the least rainy days is February (5.9 days).
Average snowfall in September
Undercliff, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.7").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Undercliff, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.2 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
Undercliff, 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: 9h and 0min
The month with the most sunshine is June (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Undercliff, IL
- Average sunshine days in September: 16.3 days
The month with the most sunshine days is November (17.7 days).
The month with the least sunshine days is May (10.7 days).
Average UV index in September
Undercliff, IL
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Undercliff, 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
Undercliff, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Undercliff, Illinois, USA
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