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 commencement of September indicates a gentle shift in the average high-temperature, receding from August's warm 82.9°F (28.3°C) to a still moderately hot 77.5°F (25.3°C). The temperature lowers to an average of 58.1°F (14.5°C) during September nights.Humidity
The average relative humidity in September is 75%.Rainfall
In September, the rain falls for 10.4 days. Throughout September, 2.4" (61mm) of precipitation is accumulated. Throughout the year, in Mendon, there are 134.2 rainfall days, and 23.15" (588mm) of precipitation is accumulated.Snowfall
In Mendon, Illinois, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:33 am and sunset at 7:36 pm. On the last day of September, sunrise is at 7:01 am and sunset at 6:48 pm CDT.
Sunshine
The average sunshine in September in Mendon is 9.4h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.Note: In September, a daily maximum UV index of 5 leads to the following instructions:
Exercise prevention - Warding off sunburn is urged. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. 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 usual temperature for Mendon 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?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Mendon, IL
- Average high temperature in September: 77.5°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (32.7°F).
- Average low temperature in September: 58.1°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).
Average pressure in September
Mendon, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Mendon, IL
- Average wind speed in September: 7.2mph
The windiest months (with the highest average wind speed) are January and February (10.3mph).
The calmest month (with the lowest average wind speed) is July (6.4mph).
Average humidity in September
Mendon, IL
- Average humidity in September: 75%
The months with the highest relative humidity are June and July (81%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Mendon, IL
- Average rainfall in September: 2.4"
The wettest month (with the highest rainfall) is May (3.35").
The driest months (with the least rainfall) are January and December (1.02").
Average rainfall days in September
Mendon, IL
- Average rainfall days in September: 10.4 days
The month with the highest number of rainy days is May (16.9 days).
The month with the least rainy days is January (5 days).
Average snowfall in September
Mendon, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.76").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Mendon, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.8 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
Mendon, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in September
Mendon, IL
- Average sunshine days in September: 18.1 days
The month with the most sunshine days is December (19.6 days).
The month with the least sunshine days is June (11.1 days).
Average UV index in September
Mendon, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Mendon, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 53).
The month with the least cloud cover is July (Cloud cover 28).
Average visibility in September
Mendon, 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).
Mendon, Illinois, USA
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