September weather forecastRosslyn Farms, PA
September
Weather in September
The first month of the autumn, September, is still a warm month in Rosslyn Farms, Pennsylvania, with an average temperature ranging between min 55.8°F (13.2°C) and max 75.7°F (24.3°C).Temperature
With the arrival of September, Rosslyn Farms experiences a modest decline in average high-temperatures, transitioning from a moderately hot 82.4°F (28°C) in August to a still warm 75.7°F (24.3°C). September brings Rosslyn Farms a consistent average low-temperature of 55.8°F (13.2°C).Humidity
In September, the average relative humidity is 77%.Rainfall
In September, the rain falls for 10.6 days. Throughout September, 0.79" (20mm) of precipitation is accumulated. In Rosslyn Farms, during the entire year, the rain falls for 132.6 days and collects up to 11.5" (292mm) of precipitation.Snowfall
May through October are months without snowfall in Rosslyn Farms.Daylight
The average length of the day in September in Rosslyn Farms is 12h and 27min.On the first day of the month, sunrise is at 6:48 am and sunset at 7:51 pm. On the last day of September, sunrise is at 7:16 am and sunset at 7:03 pm EDT.
Sunshine
In Rosslyn Farms, the average sunshine in September is 8.5h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for ordinary individuals.Note: A daily high UV index of 4 in September leads to these guidelines:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. During bright days, sunglasses that offer UVA and UVB defense are recommended.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Rosslyn Farms, PA
- Average high temperature in September: 75.7°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (33.4°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (21°F).
Average pressure in September
Rosslyn Farms, 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
Rosslyn Farms, PA
- Average wind speed in September: 5.1mph
The windiest month (with the highest average wind speed) is January (7.9mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).
Average humidity in September
Rosslyn Farms, PA
- Average humidity in September: 77%
The month with the highest relative humidity is February (85%).
The months with the lowest relative humidity are July and August (75%).
Average rainfall in September
Rosslyn Farms, PA
- Average rainfall in September: 0.79"
The wettest month (with the highest rainfall) is July (1.34").
The driest month (with the least rainfall) is November (0.67").
Average rainfall days in September
Rosslyn Farms, PA
- Average rainfall days in September: 10.6 days
The month with the highest number of rainy days is July (15.6 days).
The month with the least rainy days is February (6.4 days).
Average snowfall in September
Rosslyn Farms, PA
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.98").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Rosslyn Farms, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.3 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
Rosslyn Farms, 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 30min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).
Average sunshine days in September
Rosslyn Farms, PA
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is May (12.2 days).
Average UV index in September
Rosslyn Farms, PA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Rosslyn Farms, PA
- Average cloud cover in September: 38
The month with the most cloud cover is January (Cloud cover 68).
The month with the least cloud cover is August (Cloud cover 33).
Average visibility in September
Rosslyn Farms, 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).
