September weather forecastChevy Chase, MD
September
Weather in September
The first month of the autumn, September, is still a warm month in Chevy Chase, Maryland, with an average temperature ranging between max 78.4°F (25.8°C) and min 61.5°F (16.4°C).Temperature
A modest decline in the average high-temperature is seen during September, decreasing from 85.8°F (29.9°C) in August to a still warm 78.4°F (25.8°C). Throughout September, the average low-temperature records at a comfortable 61.5°F (16.4°C).Humidity
In Chevy Chase, the average relative humidity in September is 73%.Rainfall
In Chevy Chase, during September, the rain falls for 12.5 days and regularly aggregates up to 2.05" (52mm) of precipitation. In Chevy Chase, during the entire year, the rain falls for 150.3 days and collects up to 28.66" (728mm) of precipitation.Snowfall
May through October are months without snowfall in Chevy Chase.Daylight
The average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:52 pm EDT.
Sunshine
The average sunshine in September is 8.8h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for the average person.Note: In September, the UV index of 5 transforms into the following advice:
Ensure safety - Recommendations to avert sunburn are presented. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Chevy Chase, MD
- Average high temperature in September: 78.4°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 (39.9°F).
- Average low temperature in September: 61.5°F
The month with the highest average low temperature is July (69.4°F).
The coldest month (with the lowest average low temperature) is January (27°F).
Average pressure in September
Chevy Chase, MD
- 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
Chevy Chase, MD
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is March (8mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in September
Chevy Chase, MD
- Average humidity in September: 73%
The month with the highest relative humidity is December (76%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Chevy Chase, MD
- Average rainfall in September: 2.05"
The wettest month (with the highest rainfall) is August (3.82").
The driest month (with the least rainfall) is January (1.69").
Average rainfall days in September
Chevy Chase, MD
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is November (8.5 days).
Average snowfall in September
Chevy Chase, MD
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.6").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Chevy Chase, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.4 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
Chevy Chase, MD
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 0min).
Average sunshine days in September
Chevy Chase, MD
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (20.4 days).
The months with the least sunshine days are May and July (12.3 days).
Average UV index in September
Chevy Chase, 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, November and December (UV index 2).
Average cloud cover in September
Chevy Chase, MD
- Average cloud cover in September: 37
The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Chevy Chase, MD
- 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).
