September weather forecastWillow Grove, PA
September
Weather in September
The first month of the autumn, September, is still a warm month in Willow Grove, Pennsylvania, with an average temperature varying between 59.9°F (15.5°C) and 76.1°F (24.5°C).Temperature
With the arrival of September, Willow Grove experiences a modest decline in average high-temperatures, transitioning from 83.3°F (28.5°C) in August to a still moderately hot 76.1°F (24.5°C). The mean low-temperature during September nights is a moderate 59.9°F (15.5°C).Humidity
In September, the average relative humidity is 75%.Rainfall
September is the month with the least rainfall. Rain falls for 10.1 days and accumulates 0.75" (19mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
The average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:31 pm. On the last day of September, sunrise is at 6:56 am and sunset at 6:43 pm EDT.
Sunshine
In September, the average sunshine is 8.8h.UV index
The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the average person.Note: The maximum daily UV index, 5 in September, converts into the following recommendations:
Adopt protective measures - It is advised to guard against sun damage. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. 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
Willow Grove, PA
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (86.2°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 (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.6°F).
Average pressure in September
Willow Grove, 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
Willow Grove, PA
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is March (8.4mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).
Average humidity in September
Willow Grove, PA
- Average humidity in September: 75%
The months with the highest relative humidity are February, October and December (78%).
The months with the lowest relative humidity are April, July and August (72%).
Average rainfall in September
Willow Grove, PA
- Average rainfall in September: 0.75"
The wettest month (with the highest rainfall) is August (1.54").
The driest month (with the least rainfall) is September (0.75").
Average rainfall days in September
Willow Grove, PA
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is May (14.1 days).
The month with the least rainy days is November (6.4 days).
Average snowfall in September
Willow Grove, PA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.46").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Willow Grove, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.1 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
Willow Grove, 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 48min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Willow Grove, PA
- Average sunshine days in September: 18.5 days
The month with the most sunshine days is November (21.3 days).
The month with the least sunshine days is May (14.4 days).
Average UV index in September
Willow Grove, 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, March, November and December (UV index 2).
Average cloud cover in September
Willow Grove, PA
- Average cloud cover in September: 38
The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Willow Grove, PA
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).





