September weather forecastBryn Mawr, PA
September
Weather in September
The first month of the autumn, September, is still a warm month in Bryn Mawr, Pennsylvania, with temperature in the range of an average high of 76.5°F (24.7°C) and an average low of 59.9°F (15.5°C).Temperature
The advent of September brings a slight shift in average high-temperature, moving from a moderately hot 83.7°F (28.7°C) in August to a still warm 76.5°F (24.7°C). Throughout September, an average nighttime temperature of 59.9°F (15.5°C) is experienced.Humidity
In September, the average relative humidity in Bryn Mawr is 75%.Rainfall
In September, the rain falls for 10.1 days. Throughout September, 0.63" (16mm) of precipitation is accumulated. In Bryn Mawr, during the entire year, the rain falls for 111.8 days and collects up to 9.69" (246mm) of precipitation.Snowfall
In Bryn Mawr, snow does not fall in April through October.Daylight
The average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:29 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:44 pm EDT.
Sunshine
In September, the average sunshine is 8.6h.UV index
In Bryn Mawr, Pennsylvania, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A daily high UV index of 5 in September leads to these guidelines:
Ensure safety - Sun damage prevention is strongly urged. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Bryn Mawr, PA
- Average high temperature in September: 76.5°F
The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is January (36.7°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (68.9°F).
The coldest month (with the lowest average low temperature) is January (25°F).
Average pressure in September
Bryn Mawr, PA
- Average pressure in September: 30.05"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
Bryn Mawr, PA
- Average wind speed in September: 5.9mph
The windiest month (with the highest average wind speed) is March (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).
Average humidity in September
Bryn Mawr, PA
- Average humidity in September: 75%
The months with the highest relative humidity are February and October (78%).
The months with the lowest relative humidity are April, July and August (71%).
Average rainfall in September
Bryn Mawr, PA
- Average rainfall in September: 0.63"
The wettest months (with the highest rainfall) are July and August (1.14").
The driest month (with the least rainfall) is January (0.55").
Average rainfall days in September
Bryn Mawr, PA
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is July (13.3 days).
The month with the least rainy days is January (5.3 days).
Average snowfall in September
Bryn Mawr, PA
- Average snowfall in September: 0"
The months with the highest snowfall are February and March (0.98").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Bryn Mawr, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.5 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
Bryn Mawr, 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 24min).
- Average sunshine in September: 8h and 36min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in September
Bryn Mawr, PA
- Average sunshine days in September: 18.5 days
The month with the most sunshine days is November (22.5 days).
The month with the least sunshine days is July (14.9 days).
Average UV index in September
Bryn Mawr, PA
- 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, February, November and December (UV index 2).
Average cloud cover in September
Bryn Mawr, PA
- Average cloud cover in September: 39
The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in September
Bryn Mawr, PA
- 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).
