September weather forecastSouth Williamsport, PA
September
Weather in September
The first month of the autumn, September, is still a pleasant month in South Williamsport, Pennsylvania, with an average temperature varying between 72.1°F (22.3°C) and 51.4°F (10.8°C).Temperature
The onset of September brings a small shift in high-temperatures, falling from a warm 79.2°F (26.2°C) in August to a pleasant 72.1°F (22.3°C). The average low-temperature during September nights is a fresh 51.4°F (10.8°C).Humidity
In South Williamsport, the average relative humidity in September is 81%.Rainfall
In South Williamsport, in September, it is raining for 11.2 days, with typically 1.38" (35mm) of accumulated precipitation. Throughout the year, there are 145.2 rainfall days, and 16.57" (421mm) of precipitation is accumulated.Snowfall
In South Williamsport, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:51 pm EDT.
Sunshine
In September, the average sunshine is 8.6h.UV index
In South Williamsport, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: The UV index of 3 during September translates into the following guidance:
Heed the precautions - Suggestions to avoid sunburn are made. When the Sun is at its strongest around midday, find shade and limit exposure. Stay sun-safe with clothing that is both closely woven and worn loosely.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
South Williamsport, PA
- Average high temperature in September: 72.1°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (30.6°F).
- Average low temperature in September: 51.4°F
The month with the highest average low temperature is July (59.2°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
South Williamsport, PA
- Average pressure in September: 30.07"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
South Williamsport, PA
- Average wind speed in September: 5.3mph
The windiest months (with the highest average wind speed) are January, March and April (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
South Williamsport, PA
- Average humidity in September: 81%
The month with the highest relative humidity is February (84%).
The months with the lowest relative humidity are April and July (77%).
Average rainfall in September
South Williamsport, PA
- Average rainfall in September: 1.38"
The wettest month (with the highest rainfall) is April (1.93").
The driest month (with the least rainfall) is November (0.94").
Average rainfall days in September
South Williamsport, PA
- Average rainfall days in September: 11.2 days
The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is February (7.5 days).
Average snowfall in September
South Williamsport, PA
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
South Williamsport, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
South Williamsport, PA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 36min
The month with the most sunshine is July (Average sunshine: 10h and 6min).
The months with the least sunshine are January and February (Average sunshine: 3h and 42min).
Average sunshine days in September
South Williamsport, PA
- Average sunshine days in September: 16.8 days
The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
South Williamsport, PA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
South Williamsport, PA
- Average cloud cover in September: 41
The months with the most cloud cover are January and February (Cloud cover 60).
The month with the least cloud cover is July (Cloud cover 35).
Average visibility in September
South Williamsport, PA
- Average visibility in September: 4mi
The month with the highest visibility is April (6mi).
The month with the lowest visibility is September (4mi).
