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
As Mount Vernon transitions into September, the average high-temperature stands at a still warm 79°F (26.1°C), offering little variation from the preceding month. In the month of September, an average of 60.1°F (15.6°C) marks the low-temperature.Humidity
The average relative humidity in September in Mount Vernon is 74%.Rainfall
The month with the least rainfall in Mount Vernon is September, when the rain falls for 11.6 days and typically collects 1.61" (41mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day in Mount Vernon is 12h and 25min.On the first day of the month, sunrise is at 6:25 am and sunset at 7:24 pm. On the last day of September, in Mount Vernon, sunrise is at 6:51 am and sunset at 6:39 pm CDT.
Sunshine
In Mount Vernon, the average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index in Mount Vernon, Illinois, is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Adopt protective measures - Suggestions to resist sunburn are offered. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Mount Vernon in September?
What is the average humidity in September in Mount Vernon?
What is the driest month in Mount Vernon?
How many days does it rain in September in Mount Vernon?
When it does not snow in Mount Vernon?
What is the average length of the day in September in Mount Vernon?
When is the sunrise / sunset in September in Mount Vernon?
How long on average sun shines in September in Mount Vernon?
How high is the UV index in September in Mount Vernon?
Average temperature in September
Mount Vernon, IL
- Average high temperature in September: 79°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.9°F).
- Average low temperature in September: 60.1°F
The month with the highest average low temperature is July (67.8°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).
Average pressure in September
Mount Vernon, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Mount Vernon, IL
- Average wind speed in September: 6.5mph
The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.9mph).
Average humidity in September
Mount Vernon, IL
- Average humidity in September: 74%
The month with the highest relative humidity is May (80%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Mount Vernon, IL
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is April (3.78").
The driest month (with the least rainfall) is September (1.61").
Average rainfall days in September
Mount Vernon, IL
- Average rainfall days in September: 11.6 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is January (7.5 days).
Average snowfall in September
Mount Vernon, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.73").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Mount Vernon, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Mount Vernon, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in September
Mount Vernon, IL
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is October (20.3 days).
The month with the least sunshine days is May (11.3 days).
Average UV index in September
Mount Vernon, IL
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, November and December (UV index 2).
Average cloud cover in September
Mount Vernon, IL
- Average cloud cover in September: 28
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is June (Cloud cover 27).
Average visibility in September
Mount Vernon, 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).
Mount Vernon, Illinois, USA
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