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
With the beginning of September, the average high-temperature shows a small decrease, transitioning from a warm 82.8°F (28.2°C) in August to a still moderately hot 77°F (25°C). Vienna's average low-temperature in the month of September is recorded at an enjoyable 63.1°F (17.3°C).Humidity
May, August and September, with an average relative humidity of 80%, are the most humid months.Rainfall
In Vienna, during September, the rain falls for 10.3 days and regularly aggregates up to 0.98" (25mm) of precipitation. Throughout the year, there are 114.4 rainfall days, and 12.05" (306mm) of precipitation is accumulated.Snowfall
In Vienna, snow does not fall in May through October.Daylight
In Vienna, the average length of the day in September is 12h and 25min.On the first day of September in Vienna, sunrise is at 6:33 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:47 pm EDT.
Sunshine
The average sunshine in September is 9h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: In September, the maximum UV index of 5 suggests this advice:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the most humid month?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
How many hours of daylight does Vienna have in September?
When is the sunrise / sunset in September in Vienna?
How long on average sun shines in September?
What is the UV index intensity in September in Vienna?
Average temperature in September
Vienna, MD
- Average high temperature in September: 77°F
The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (42.1°F).
- Average low temperature in September: 63.1°F
The month with the highest average low temperature is July (70.2°F).
The coldest month (with the lowest average low temperature) is January (29.5°F).
Average pressure in September
Vienna, MD
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Vienna, MD
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is February (9.7mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).
Average humidity in September
Vienna, MD
- Average humidity in September: 80%
The months with the highest relative humidity are May, August and September (80%).
The months with the lowest relative humidity are January, February, March and April (75%).
Average rainfall in September
Vienna, MD
- Average rainfall in September: 0.98"
The wettest month (with the highest rainfall) is July (1.46").
The driest months (with the least rainfall) are April and May (0.79").
Average rainfall days in September
Vienna, MD
- Average rainfall days in September: 10.3 days
The month with the highest number of rainy days is July (13.2 days).
The month with the least rainy days is November (6.5 days).
Average snowfall in September
Vienna, MD
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.75").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Vienna, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (3.2 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
Vienna, MD
- 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 42min).
The months with the least sunshine are February and December (Average sunshine: 5h and 6min).
Average sunshine days in September
Vienna, MD
- Average sunshine days in September: 17 days
The month with the most sunshine days is November (21.2 days).
The month with the least sunshine days is July (14.7 days).
Average UV index in September
Vienna, MD
- 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
Vienna, MD
- Average cloud cover in September: 35
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 28).
Average visibility in September
Vienna, MD
- 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).
Vienna, Maryland, USA
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