September weather forecastKing of Prussia, PA
September
Weather in September
September in King of Prussia brings the transition from summer to autumn, resulting in slight changes in daily weather patterns. Gradually, the temperatures start to cool down, and days become shorter. The frequency of rainfall decreases from the summer months, and the lush greenery begins to burst into autumnal hues. Notably, in September temperature varies between 59°F (15°C) and 76.1°F (24.5°C), and the city experiences approximately 0.98" (25mm) of rainfall in 10 days. The arrival of fall can be observed clearly as September comes to an end.Temperature
In King of Prussia, the beginning of September is marked by a marginally lowered average high-temperature, shifting from August's moderately hot 83.3°F (28.5°C) to a still warm 76.1°F (24.5°C). King of Prussia records a mean low-temperature of 59°F (15°C) in September.Humidity
In September, the average relative humidity is 76%.Rainfall
In King of Prussia, Pennsylvania, during September, the rain falls for 10.8 days and regularly aggregates up to 0.98" (25mm) of precipitation. Throughout the year, there are 138.2 rainfall days, and 15.59" (396mm) of precipitation is accumulated.Snowfall
In King of Prussia, snow does not fall in April, June through November.Daylight
The average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:29 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:44 pm EDT.
Sunshine
In September, the average sunshine is 8.8h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum UV index of 4 during September translates into these guidelines:
Exercise prevention - Warding off sunburn is urged. Direct Sun exposure should be minimized especially during midday when radiation is most intense. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
King of Prussia, PA
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (36.7°F).
- Average low temperature in September: 59°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in September
King of Prussia, PA
- Average pressure in September: 30.06"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
King of Prussia, PA
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest months (with the lowest average wind speed) are July and August (5.3mph).
Average humidity in September
King of Prussia, PA
- Average humidity in September: 76%
The months with the highest relative humidity are February and October (79%).
The months with the lowest relative humidity are April and July (72%).
Average rainfall in September
King of Prussia, PA
- Average rainfall in September: 0.98"
The wettest month (with the highest rainfall) is July (1.89").
The driest month (with the least rainfall) is February (0.91").
Average rainfall days in September
King of Prussia, PA
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is May (16 days).
The month with the least rainy days is November (7.4 days).
Average snowfall in September
King of Prussia, PA
- Average snowfall in September: 0"
The months with the highest snowfall are February and March (0.55").
The months with the least snowfall are April, June, July, August, September, October and November (0").
Average snowfall days in September
King of Prussia, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.2 days).
The months with the least snowfall days are April, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
King of Prussia, 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
King of Prussia, PA
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is November (20.5 days).
The months with the least sunshine days are May and June (12.8 days).
Average UV index in September
King of Prussia, PA
- Average UV index in September: 4
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
King of Prussia, 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 32).
Average visibility in September
King of Prussia, 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).





