September weather forecastBrentwood, PA
September
Weather in September
The first month of the autumn, September, is still a warm month in Brentwood, Pennsylvania, with an average temperature fluctuating between 75.7°F (24.3°C) and 55.9°F (13.3°C).Temperature
With the onset of September, the average high-temperature subtly recedes from August's warm 82.2°F (27.9°C) to a still moderately hot 75.7°F (24.3°C). In Brentwood, an average low-temperature of 55.9°F (13.3°C) is recorded during September nights.Humidity
The average relative humidity in September is 76%.Rainfall
In Brentwood, in September, it is raining for 13.5 days, with typically 2.2" (56mm) of accumulated precipitation. In Brentwood, during the entire year, the rain falls for 164 days and collects up to 26.89" (683mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 27min.On the first day of September, sunrise is at 6:48 am and sunset at 7:51 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 7:03 pm EDT.
Sunshine
In September, the average sunshine is 8.4h.UV index
In Brentwood, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: An average maximum UV index of 4 in September leads to these recommendations:
Exercise care. People with light skin might get burns in fewer than 30 minutes. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Brentwood, PA
- Average high temperature in September: 75.7°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (33.4°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (20.8°F).
Average pressure in September
Brentwood, PA
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in September
Brentwood, PA
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is January (7.9mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in September
Brentwood, PA
- Average humidity in September: 76%
The months with the highest relative humidity are January and February (84%).
The month with the lowest relative humidity is August (73%).
Average rainfall in September
Brentwood, PA
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is November (1.61").
Average rainfall days in September
Brentwood, PA
- Average rainfall days in September: 13.5 days
The month with the highest number of rainy days is May (18.4 days).
The month with the least rainy days is January (8.5 days).
Average snowfall in September
Brentwood, PA
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.46").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Brentwood, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (16.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Brentwood, PA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 24min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 2h and 54min).
Average sunshine days in September
Brentwood, PA
- Average sunshine days in September: 14 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is February (9.5 days).
Average UV index in September
Brentwood, PA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Brentwood, PA
- Average cloud cover in September: 39
The month with the most cloud cover is January (Cloud cover 69).
The month with the least cloud cover is August (Cloud cover 34).
Average visibility in September
Brentwood, PA
- Average visibility in September: 5mi
The months with the highest visibility are April, June, July, August and November (6mi).
The months with the lowest visibility are January, February, March, May, September, October and December (5mi).





