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 arrival of September, Washington experiences a modest decline in average high-temperatures, transitioning from 83.1°F (28.4°C) in August to a still warm 76.1°F (24.5°C). Washington sees an average low-temperature of 56.1°F (13.4°C) during September.Humidity
In Washington, the average relative humidity in September is 78%.Rainfall
In Washington, in September, during 13.6 rainfall days, 1.54" (39mm) of precipitation is typically accumulated. In Washington, Virginia, during the entire year, the rain falls for 146.8 days and collects up to 21.02" (534mm) of precipitation.Snowfall
In Washington, snow does not fall in June through September.Daylight
The average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:42 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:08 am and sunset at 6:56 pm EDT.
Sunshine
The average sunshine in September is 8.6h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: An average maximum UV index of 4 in September leads to these recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow in Washington?
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
Washington, VA
- Average high temperature in September: 76.1°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 (38.7°F).
- Average low temperature in September: 56.1°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (23.9°F).
Average pressure in September
Washington, 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
Washington, VA
- Average wind speed in September: 4.5mph
The windiest months (with the highest average wind speed) are February and March (6.7mph).
The calmest month (with the lowest average wind speed) is August (4.1mph).
Average humidity in September
Washington, VA
- Average humidity in September: 78%
The month with the highest relative humidity is October (79%).
The months with the lowest relative humidity are April and July (74%).
Average rainfall in September
Washington, VA
- Average rainfall in September: 1.54"
The wettest month (with the highest rainfall) is May (2.64").
The driest month (with the least rainfall) is January (0.94").
Average rainfall days in September
Washington, VA
- Average rainfall days in September: 13.6 days
The month with the highest number of rainy days is August (17.8 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in September
Washington, VA
- Average snowfall in September: 0"
The month with the highest snowfall is March (2.56").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Washington, VA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Washington, 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: 8h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).
Average sunshine days in September
Washington, VA
- Average sunshine days in September: 14.1 days
The month with the most sunshine days is November (20.9 days).
The month with the least sunshine days is August (11.4 days).
Average UV index in September
Washington, VA
- Average UV index in September: 4
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, February, November and December (UV index 2).
Average cloud cover in September
Washington, VA
- Average cloud cover in September: 39
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Washington, VA
- Average visibility in September: 5mi
The months with the highest visibility are January, February, April, June, July, August and November (6mi).
The months with the lowest visibility are March, May, September, October and December (5mi).
Washington, Virginia, USA
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