September weather forecast
Valley Forge, PA

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Weather in September

September, the first month of the autumn in Valley Forge, is still a warm month, with temperature in the range of an average low of 58.6°F (14.8°C) and an average high of 75.7°F (24.3°C).

Temperature

September's onset brings a negligible change in high-temperatures, falling from 82.8°F (28.2°C) in August to a still warm 75.7°F (24.3°C). In the month of September, Valley Forge witnesses a consistent average low-temperature of 58.6°F (14.8°C).

Humidity

In September, the average relative humidity is 77%.

Rainfall

In Valley Forge, in September, it is raining for 11.8 days, with typically 0.91" (23mm) of accumulated precipitation. In Valley Forge, during the entire year, the rain falls for 132.3 days and collects up to 13.98" (355mm) of precipitation.

Snowfall

In Valley Forge, snow does not fall in April through October.

Daylight

In Valley Forge, Pennsylvania, the average length of the day in September is 12h and 26min.
On the first day of September, sunrise is at 6:30 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm EDT.

Sunshine

The average sunshine in September in Valley Forge, Pennsylvania, is 8.7h.

UV index

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum UV index of 4 during September translates into these guidelines:
Exercise caution. Those with pale skin may experience burns in less than half an hour. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.

Frequently asked questions

What is the usual temperature for Valley Forge in September?

Valley Forge in September has an average high-temperature of 75.7°F (24.3°C) and an average low-temperature of 58.6°F (14.8°C). In August, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which represents the influence of relative humidity on air temperature, is computed to be 89.6°F (32°C).

What is the average humidity in September?

In Valley Forge, Pennsylvania, the average relative humidity in September is 77%.

How many days does it rain in September?

In Valley Forge, Pennsylvania, in September, it is raining for 11.8 days, with typically 0.91" (23mm) of accumulated precipitation.

When it does not snow?

April through October are months without snowfall.

What is the average length of the day in September?

In Valley Forge, the average day length in September is 12h and 26min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:30 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm EDT.

How many hours of sunshine does Valley Forge have in September?

The average sunshine duration in September is 8.7h.

What is the UV index reading in September?

The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Valley Forge, PA

Average temperature in September - Valley Forge, PA
  • Average high temperature in September: 75.7°F

The warmest month (with the highest average high temperature) is July (85.1°F).
The month with the lowest average high temperature is January (36°F).

  • Average low temperature in September: 58.6°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (23.9°F).

Average pressure in September
Valley Forge, PA

Average pressure in September - Valley Forge, 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
Valley Forge, PA

Average wind speed in September - Valley Forge, PA
  • Average wind speed in September: 5.6mph

The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).

Average humidity in September
Valley Forge, PA

Average humidity in September - Valley Forge, PA
  • Average humidity in September: 77%

The month with the highest relative humidity is February (80%).
The months with the lowest relative humidity are April and July (74%).

Average rainfall in September
Valley Forge, PA

Average rainfall in September - Valley Forge, PA
  • Average rainfall in September: 0.91"

The wettest month (with the highest rainfall) is August (1.77").
The driest month (with the least rainfall) is February (0.75").

Average rainfall days in September
Valley Forge, PA

Average rainfall days in September - Valley Forge, PA
  • Average rainfall days in September: 11.8 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is January (6.9 days).

Average snowfall in September
Valley Forge, PA

Average snowfall in September - Valley Forge, PA
  • Average snowfall in September: 0"

The months with the highest snowfall are January and February (0.59").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Valley Forge, PA

Average snowfall days in September - Valley Forge, PA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (4.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Valley Forge, PA

Average daylight in September / Average sunshine in September - Valley Forge, 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 4min

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 36min).

Average sunshine days in September
Valley Forge, PA

Average sunshine days in September - Valley Forge, PA
  • Average sunshine days in September: 17 days

The month with the most sunshine days is January (20.7 days).
The month with the least sunshine days is June (12.8 days).

Average UV index in September
Valley Forge, PA

Average UV index in September - Valley Forge, 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
Valley Forge, PA

Average cloud cover in September - Valley Forge, PA
  • Average cloud cover in September: 39

The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 32).

Average visibility in September
Valley Forge, PA

Average visibility in September - Valley Forge, 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).

Valley Forge, Pennsylvania, USA

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