Philadelphia
Pennsylvania, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Philadelphia, PA

The George Washington statue in front of the Independence Hall in Philadelphia, Pennsylvania
The George Washington statue in front of the Independence Hall in Philadelphia, Pennsylvania
September crowns the summer amid warm and pleasant weather. The mercury drops to the warm and pleasant range of 60.3°F (15.7°C) to 78.1°F (25.6°C), and the excess summer heat dies off.
The highest humidity of the year is registered in September, averaging 71.6%, and the days feel muggy but tolerable. With up to seven hours of sunshine, tourists still enjoy outdoor activities late into the evening. An increase in rainfall sees Philadelphia register moderately high precipitation of 3.8" (96.5mm), collected from approximately eight and a half rainfall days.
The crowds in Philadelphia begin to thin out as summer comes to an end, leaving enough room to tour the various attraction spots without a hustle.

What is the temperature in September in Philadelphia?

In Philadelphia, in September, the average high-temperature is 78.1°F (25.6°C), and the average low-temperature is 60.3°F (15.7°C).

What is the most humid month in Philadelphia?

The most humid month in Philadelphia, Pennsylvania, is September, with an average relative humidity of 71.6%.

What is the average humidity in September in Philadelphia?

The average relative humidity in September is 71.6%.

How much does it rain in Philadelphia in September?

In Philadelphia, Pennsylvania, during September, the rain falls for 8.7 days and regularly aggregates up to 3.8" (96mm) of precipitation.

What is the ocean temperature in September in Philadelphia?

In Philadelphia, Pennsylvania, the average seawater temperature in September is 71.4°F (21.9°C). Swimming in 71.4°F (21.9°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

How many hours of daylight does Philadelphia have in September?

In Philadelphia, Pennsylvania, the average length of the day in September is 12.4h.

How many hours of sunshine does Philadelphia have in September?

In Philadelphia, Pennsylvania, the average sunshine in September is 7.3h.

What is the UV index reading in September in Philadelphia?

In September, the average daily maximum UV index in Philadelphia is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from the exposure to the Sun's UV rays.
Average temperature in September - Philadelphia, PA
  • Average high temperature in September: 78°F

The warmest month (with the highest average high temperature) is July (87.1°F).
The month with the lowest average high temperature is January (40.3°F).

  • Average low temperature in September: 60.3°F

The month with the highest average low temperature is July (69.2°F).
The coldest month (with the lowest average low temperature) is January (25.6°F).

Average humidity in September - Philadelphia, PA
  • Average humidity in September: 71.6%

The month with the highest relative humidity is September (71.6%).
The month with the lowest relative humidity is April (60.4%).

Average rainfall in September - Philadelphia, PA
  • Average rainfall in September: 3.8"

The wettest month (with the highest rainfall) is July (4.4").
The driest month (with the lowest rainfall) is February (2.7").

Average rainfall days in September - Philadelphia, PA
  • Average rainfall days in September: 8.7 days

The month with the highest number of rainy days is April (11.3 days).
The month with the lowest number of rainy days is August (8.4 days).

Average snowfall in September - Philadelphia, PA
  • Average snowfall in September: 0"

The month with the highest snowfall is February (8.8").
Months with the lowest snowfall are May, June, July, August, September and October (0").

Average snowfall days in September - Philadelphia, PA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (4.4 days).
Months with the lowest number of snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature in September - Philadelphia, PA
  • Average sea temperature in September: 71.4°F

The best month for swimming (with the highest average sea temperature) is August (75.9°F).
The coldest month (with the lowest average sea temperature) is February (39.9°F).

Average daylight in September / Average sunshine in September - Philadelphia, PA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15h).
The month with shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 7.3h

The month with most sunshine is June (Average sunshine: 9h).
The month with least sunshine is December (Average sunshine: 4.4h).

Average UV index in September - Philadelphia, PA
  • Average UV index in September: 6

Months with the highest UV index are June and July (UV index 9).
Months with the lowest UV index are January, November and December (UV index 2).