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 arrival of September marks a slight shift to an average high-temperature of a still moderately hot 74.1°F (23.4°C) from August's 79.3°F (26.3°C). An average nighttime temperature of 54.9°F (12.7°C) is noted during the month of September.Humidity
The average relative humidity in September in Mount Vernon is 78%.Rainfall
In Mount Vernon, during September, the rain falls for 12 days and regularly aggregates up to 2.72" (69mm) of precipitation. Throughout the year, there are 147.9 rainfall days, and 31.57" (802mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
In Mount Vernon, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:32 am and sunset at 7:38 pm. On the last day of September, in Mount Vernon, sunrise is at 7:02 am and sunset at 6:48 pm CDT.
Sunshine
In September, the average sunshine in Mount Vernon, Iowa, is 9.2h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: The daily high UV index of 4 during September translates into the following recommendations:
Take measures. Individuals with light skin might experience burns in under 30 minutes. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Frequently asked questions
What are September temperatures in Mount Vernon?
What is the average humidity in September in Mount Vernon?
How many days does it rain in September in Mount Vernon?
When it does not snow in Mount Vernon?
Does it snow in Mount Vernon in September?
How many hours of daylight does Mount Vernon have in September?
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, IA
- Average high temperature in September: 74.1°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (26.2°F).
- Average low temperature in September: 54.9°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 (14.2°F).
Average pressure in September
Mount Vernon, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Mount Vernon, IA
- Average wind speed in September: 8mph
The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in September
Mount Vernon, IA
- Average humidity in September: 78%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Mount Vernon, IA
- Average rainfall in September: 2.72"
The wettest month (with the highest rainfall) is May (5").
The driest month (with the least rainfall) is January (1.34").
Average rainfall days in September
Mount Vernon, IA
- Average rainfall days in September: 12 days
The month with the highest number of rainy days is May (19 days).
The months with the least rainy days are January and February (5.2 days).
Average snowfall in September
Mount Vernon, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.79").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Mount Vernon, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Mount Vernon, IA
- 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 12min).
- Average sunshine in September: 9h and 1min
The months with the most sunshine are July and August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Mount Vernon, IA
- Average sunshine days in September: 15.9 days
The month with the most sunshine days is November (17 days).
The month with the least sunshine days is June (8.1 days).
Average UV index in September
Mount Vernon, IA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Mount Vernon, IA
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 58).
The months with the least cloud cover are August and September (Cloud cover 31).
Average visibility in September
Mount Vernon, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Mount Vernon, Iowa, USA
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