September weather forecastBrentwood, MD
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Brentwood, Maryland, with an average temperature varying between 62.2°F (16.8°C) and 78.1°F (25.6°C).Temperature
Transition into September subtly marks a drop in the average high-temperature, moderately moving from a warm 85.1°F (29.5°C) in August to a still moderately hot 78.1°F (25.6°C). Brentwood's temperature lowers to a mean of 62.2°F (16.8°C) during the nights in September.Humidity
In September, the average relative humidity is 74%.Rainfall
In Brentwood, in September, it is raining for 12.3 days, with typically 2.09" (53mm) of accumulated precipitation. In Brentwood, Maryland, during the entire year, the rain falls for 157.9 days and collects up to 31.14" (791mm) of precipitation.Snowfall
In Brentwood, snow does not fall in May through November.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:37 pm. On the last day of September, sunrise is at 7:03 am and sunset at 6:51 pm EDT.
Sunshine
In September, the average sunshine is 9.1h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the average person.Note: In September, an average UV index of 5 transforms into the following instructions:
Take necessary precautions - Suggestions to elude sunburn are provided. It's recommended to limit sun exposure when its radiation is at its peak during midday. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Brentwood, MD
- Average high temperature in September: 78.1°F
The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (39.9°F).
- Average low temperature in September: 62.2°F
The month with the highest average low temperature is July (70°F).
The coldest month (with the lowest average low temperature) is January (27.7°F).
Average pressure in September
Brentwood, 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 (29.94"Hg).
Average wind speed in September
Brentwood, MD
- Average wind speed in September: 6.1mph
The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in September
Brentwood, MD
- 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
Brentwood, MD
- Average rainfall in September: 2.09"
The wettest month (with the highest rainfall) is August (3.58").
The driest month (with the least rainfall) is January (2.01").
Average rainfall days in September
Brentwood, MD
- Average rainfall days in September: 12.3 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is November (9 days).
Average snowfall in September
Brentwood, 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, October and November (0").
Average snowfall days in September
Brentwood, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.1 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
Brentwood, 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: 9h and 6min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).
Average sunshine days in September
Brentwood, MD
- Average sunshine days in September: 15.6 days
The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
Brentwood, 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
Brentwood, MD
- 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 29).
Average visibility in September
Brentwood, 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).





