September weather forecastSouth Mountain, PA
September
Weather in September
September, the first month of the autumn in South Mountain, is also a moderately hot month, with an average temperature varying between 55.9°F (13.3°C) and 74.8°F (23.8°C).Temperature
The advent of September brings a slight shift in average high-temperature, moving from a moderately hot 81.7°F (27.6°C) in August to a still warm 74.8°F (23.8°C). Nighttime temperatures consistently average a moderate 55.9°F (13.3°C) during September.Humidity
The average relative humidity in September in South Mountain is 79%.Rainfall
The month with the least rainfall is September, when the rain falls for 10 days and typically collects 0.55" (14mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 26min.On the first day of September, sunrise is at 6:38 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:53 pm EDT.
Sunshine
In South Mountain, the average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: A daily maximum UV index of 4 in September translates into the following instructions:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. To cut down UV radiation exposure by about half, sport a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
South Mountain, PA
- Average high temperature in September: 74.8°F
The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (35.4°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (63.7°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in September
South Mountain, PA
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in September
South Mountain, PA
- Average wind speed in September: 5.3mph
The windiest month (with the highest average wind speed) is January (8mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).
Average humidity in September
South Mountain, PA
- Average humidity in September: 79%
The months with the highest relative humidity are February, May and October (80%).
The month with the lowest relative humidity is July (75%).
Average rainfall in September
South Mountain, PA
- Average rainfall in September: 0.55"
The wettest month (with the highest rainfall) is May (1.26").
The driest month (with the least rainfall) is September (0.55").
Average rainfall days in September
South Mountain, PA
- Average rainfall days in September: 10 days
The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is January (5.4 days).
Average snowfall in September
South Mountain, PA
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.06").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
South Mountain, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.7 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
South Mountain, 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 42min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days in September
South Mountain, PA
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is November (21.7 days).
The month with the least sunshine days is May (12.9 days).
Average UV index in September
South Mountain, PA
- Average UV index in September: 4
The months with the highest UV index are 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
South Mountain, PA
- Average cloud cover in September: 38
The months with the most cloud cover are January and February (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in September
South Mountain, PA
- Average visibility in September: 5mi
The months with the highest visibility are March, April, June, July, November and December (6mi).
The months with the lowest visibility are January, February, May, August, September and October (5mi).
