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 advent of September brings a subtle shift in temperature, with the average high moving from 85.6°F (29.8°C) in August to a still moderately hot 78.6°F (25.9°C). Mount Vernon observes an average low-temperature of 61.7°F (16.5°C) during September.Humidity
In September, the average relative humidity in Mount Vernon is 74%.Rainfall
September is the month with the least rainfall. Rain falls for 11.9 days and accumulates 1.93" (49mm) of precipitation.Snowfall
In Mount Vernon, snow does not fall in May through October.Daylight
In September, the average length of the day is 12h and 26min.On the first day of September, sunrise is at 6:38 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:52 pm EDT.
Sunshine
In Mount Vernon, the average sunshine in September is 9h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for average individuals.Note: The UV index of 5 during September translates into the following guidance:
Put precautions into practice - Protective measures against sun-induced damage are advised. Around midday, solar radiation is most harmful; hence, exposure should be limited. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Frequently asked questions
What is the usual temperature for Mount Vernon in September?
What is the average humidity in September in Mount Vernon?
What is the driest month in Mount Vernon?
How much does it rain in Mount Vernon in September?
When it does not snow in Mount Vernon?
How many hours of daylight does Mount Vernon have in September?
When are sunrise and 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, VA
- Average high temperature in September: 78.6°F
The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is January (40.6°F).
- Average low temperature in September: 61.7°F
The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (27.7°F).
Average pressure in September
Mount Vernon, VA
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in September
Mount Vernon, VA
- Average wind speed in September: 5.6mph
The windiest month (with the highest average wind speed) is March (7.8mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in September
Mount Vernon, VA
- Average humidity in September: 74%
The months with the highest relative humidity are May, October and December (76%).
The months with the lowest relative humidity are April and July (71%).
Average rainfall in September
Mount Vernon, VA
- Average rainfall in September: 1.93"
The wettest month (with the highest rainfall) is August (3.43").
The driest month (with the least rainfall) is September (1.93").
Average rainfall days in September
Mount Vernon, VA
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is November (8.5 days).
Average snowfall in September
Mount Vernon, VA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.48").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Mount Vernon, VA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.5 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, VA
- 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 30min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 6min).
Average sunshine days in September
Mount Vernon, VA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is November (19.8 days).
The month with the least sunshine days is May (11.5 days).
Average UV index in September
Mount Vernon, VA
- 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 and December (UV index 2).
Average cloud cover in September
Mount Vernon, VA
- Average cloud cover in September: 36
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in September
Mount Vernon, VA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Mount Vernon, Virginia, USA
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