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 sea temperature 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
A mild drop in Philadelphia's average high-temperature is observed in September, transitioning from a moderately hot 84°F (28.9°C) in August to a still warm 76.6°F (24.8°C). In September, the temperature drops to an average of 61.2°F (16.2°C) at night.Humidity
The average relative humidity in September is 75%.Rainfall
In Philadelphia, during September, the rain falls for 10.5 days and regularly aggregates up to 0.87" (22mm) of precipitation. In Philadelphia, during the entire year, the rain falls for 127.8 days and collects up to 13.82" (351mm) of precipitation.Snowfall
In Philadelphia, snow does not fall in June through October.Ocean temperature
In September, the average ocean temperature is 71.4°F (21.9°C).Note: A surface water temperature of 71.4°F (21.9°C) does not provide an enjoyable swimming experience for most. Breathing control becomes more challenging as the water temperature drops below 69.8°F (21°C).
Daylight
In Philadelphia, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:31 pm. On the last day of September, sunrise is at 6:56 am and sunset at 6:44 pm EDT.
Sunshine
In September, the average sunshine is 8.8h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum daily UV index, 5 in September, converts into the following recommendations:
Exercise prevention - Warding off sunburn is urged. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Be wary! Reflections from sand and water make UV radiation more intense.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
What is the ocean temperature in September?
How many hours of daylight does Philadelphia have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Philadelphia have in September?
What is the UV index intensity in September?
Average temperature in September
Philadelphia, PA
- Average high temperature in September: 76.6°F
The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (37.4°F).
- Average low temperature in September: 61.2°F
The month with the highest average low temperature is July (69.3°F).
The coldest month (with the lowest average low temperature) is January (25.5°F).
Average pressure in September
Philadelphia, PA
- Average pressure in September: 30.05"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
Philadelphia, PA
- Average wind speed in September: 6mph
The windiest months (with the highest average wind speed) are March and April (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).
Average humidity in September
Philadelphia, PA
- Average humidity in September: 75%
The month with the highest relative humidity is October (77%).
The months with the lowest relative humidity are April and August (71%).
Average rainfall in September
Philadelphia, PA
- Average rainfall in September: 0.87"
The wettest month (with the highest rainfall) is August (1.65").
The driest months (with the least rainfall) are January and February (0.83").
Average rainfall days in September
Philadelphia, PA
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is July (14.8 days).
The month with the least rainy days is February (7.2 days).
Average snowfall in September
Philadelphia, PA
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.98").
The months with the least snowfall are 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 (3.8 days).
The months with the least snowfall days are 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: 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 July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Philadelphia, PA
- Average sunshine days in September: 17.4 days
The month with the most sunshine days is December (20.9 days).
The month with the least sunshine days is May (13.3 days).
Average UV index in September
Philadelphia, PA
- Average UV index in September: 5
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, November and December (UV index 2).
Average cloud cover in September
Philadelphia, PA
- Average cloud cover in September: 38
The months with the most cloud cover are February and March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Philadelphia, PA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Philadelphia, Pennsylvania, USA
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