Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
With the onset of September, the average high-temperature subtly recedes from August's 80.6°F (27°C) to a still moderately hot 74.3°F (23.5°C). Southwest, during the month of September, experiences an average low-temperature of 54.1°F (12.3°C).Humidity
The average relative humidity in September is 78%.Rainfall
In Southwest, in September, it is raining for 15.3 days, with typically 2.2" (56mm) of accumulated precipitation. In Southwest, during the entire year, the rain falls for 185.4 days and collects up to 34.02" (864mm) of precipitation.Snowfall
In Southwest, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 6:46 am and sunset at 7:49 pm. On the last day of September, sunrise is at 7:14 am and sunset at 7:01 pm EDT.
Sunshine
The average sunshine in September is 8.8h.UV index
In Southwest, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.Note: In September, a daily maximum UV index of 4 leads to the following instructions:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Southwest have in September?
What is the UV index intensity in September in Southwest?
Average temperature in September
Southwest, PA
- Average high temperature in September: 74.3°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (33.3°F).
- Average low temperature in September: 54.1°F
The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is January (20.3°F).
Average pressure in September
Southwest, 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
Southwest, PA
- Average wind speed in September: 5.3mph
The windiest month (with the highest average wind speed) is January (8.5mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Southwest, PA
- Average humidity in September: 78%
The months with the highest relative humidity are January and February (85%).
The months with the lowest relative humidity are April, July and August (77%).
Average rainfall in September
Southwest, PA
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is May (3.66").
The driest month (with the least rainfall) is November (2.01").
Average rainfall days in September
Southwest, PA
- Average rainfall days in September: 15.3 days
The month with the highest number of rainy days is May (22 days).
The month with the least rainy days is January (9.8 days).
Average snowfall in September
Southwest, PA
- Average snowfall in September: 0"
The month with the highest snowfall is January (7.09").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Southwest, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (17.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Southwest, PA
- Average daylight in September: 12h and 2min
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 5min
The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).
Average sunshine days in September
Southwest, PA
- Average sunshine days in September: 13.3 days
The month with the most sunshine days is November (13.5 days).
The month with the least sunshine days is January (6.5 days).
Average UV index in September
Southwest, PA
- Average UV index in September: 4
The month with the highest UV index is July (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
Southwest, PA
- Average cloud cover in September: 38
The month with the most cloud cover is January (Cloud cover 69).
The month with the least cloud cover is August (Cloud cover 35).
Average visibility in September
Southwest, PA
- Average visibility in September: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January and February (4mi).
Southwest, Pennsylvania, USA
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