Are you considering a trip to Philadelphia in September? Well, the weather is usually on your side with an average maximum temperature of +26°C and about 7 sunny days. Just keep in mind that there may be some rain, with an average of 12 rainy days and 100 mm of precipitation. Expect good weather and pack accordingly to enjoy the outdoors. Search flightsin one click on Avionero.
Good to know:
September is usually the wettest month of the year in Philadelphia;
Average weather
☀️
+26°C
Avg. max. temperature
+4°C
Min.
+36°C
Max.
100 mm
Total precipitation
72%
Avg. humidity
2 m/s
Avg. wind
7 ☀️
Sunny Days
11 ⛅️
Cloudy
12 🌦
Rainy
Our opinion: Philadelphia has good weather in September.
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Average temperature in Philadelphia in September
Here are the expected maximum, average and minimum temperatures in Philadelphia for September based on the historical data.
Last Year
Historical Data
The temperature in September is +26°C on average, with a range between a maximum of +36°C during the day and a minimum of +12°C at night.
The average maximum temperature goes down 21% by the end of the month, compared with the beginning of the month, from +26°C to +21°C.
Is Philadelphia warm or cold in September?
Philadelphia is typically warm in September.
Maximum temperatures go down compared to the previous month from +29°C to +26°C. The minimum temperature also goes down from +21°C to +17°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
Take a look at how September is compared to other months in Philadelphia:
Climate in Philadelphia in September
Philadelphia weather looks like this, on average, in September and the surrounding months.
August
September
October
Avg. temperature
+29°C
+26°C
+19°C
Min. temperature
+9°C
+4°C
-2°C
Max. temperature
+38°C
+36°C
+34°C
Rainfall
99 mm
100 mm
90 mm
Wind
2 m/s
2 m/s
3 m/s
Humidity
71%
72%
71%
Air pressure
1015 HPa
1017 HPa
1017 HPa
Sunny days
5
7
8
Cloudy days
10
11
12
Rainy days
15
12
11
Snowy days
0
0
0
September weather is still as good as in August.It’s getting colder in September. From +29°C in the day, the average maximum temperature lowers to +26°C.Prepare for more rain. Average rainfall goes from 99 mm to 100 mm.Humidity rises from 71% to 72%.The average wind speed doesn’t change much during September, staying around 2 m/s.The good news is there are likely to be more sunny days in September, from 5 to 7.
October brings much the same weather, it remains good.
Wind speed in Philadelphia in September based on historical data.
Last Year
Historical Data
The average wind speed is 3 m/s getting up to 8 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Philadelphia is gradually increasing during September, going from 3 m/s to 4 m/s over the course of the month.
Rain
Amount of rainfall in mm during September in Philadelphia based on historical data.
Last Year
Historical Data
A chance of rain on a typical day in September stands at 47%, leading to total precipitation of around 295 mm. The maximum amount of rainfall per day is around 72 mm, which is considered heavy rain.September is a pretty wet month with over 14 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of galoshes.
September is one of the rainiest months in Philadelphia, here is a comparison with other months, total mm:
Philadelphia wettest month is July, where a typical day has a 52% chance of precipitation and 102 mm of rainfall per day. February, on the other hand, is the driest month with a mere 25% chance of precipitation and 50 mm of rainfall per day.
How was the weather last September in Philadelphia?
This is the weather in Philadelphia in September 2025:
1 September
☀️
+26°C
2 September
☀️
+28°C
3 September
☀️
+33°C
4 September
☁️
+36°C
5 September
☁️
+34°C
6 September
☁️
+35°C
7 September
☁️
+36°C
8 September
☁️
+35°C
9 September
🌧️
+30°C
10 September
🌧️
+28°C
11 September
🌧️
+29°C
12 September
☁️
+30°C
13 September
☁️
+28°C
14 September
☀️
+26°C
15 September
☀️
+25°C
16 September
☁️
+26°C
17 September
☀️
+27°C
18 September
🌫️
+22°C
19 September
☀️
+24°C
20 September
☁️
+25°C
21 September
☀️
+24°C
22 September
☁️
+22°C
23 September
☁️
+18°C
24 September
🌫️
+19°C
25 September
🌫️
+18°C
26 September
🌧️
+16°C
27 September
☁️
+20°C
28 September
☁️
+17°C
29 September
🌧️
+19°C
30 September
☁️
+21°C
In September 2025 Philadelphia had 8 sunny days, 14 cloudy days, and 5 rainy days. The average maximum temperature was +26°C, with an absolute maximum of +36°C and a minimum of +16°C. The average humidity was 74%, with a maximum of 100% and a minimum of 38%. The average wind speed was 3 m/s, with a maximum of 10 m/s and a minimum of 0 m/s.
Are you planning a trip in September?
Climate Change over Years
This is how Philadelphia climate have been changing during last 43 years period.
The climate in Philadelphia in September has not changed much over the last 43 years.
The average temperature was the lowest in 1996 (+17°C) and the highest in 2012 (+20°C). The driest year was 2001 with only 685 mm of rainfall, and the wettest year was 2023 with 1758 mm.
FAQ
Frequently asked questions about the weather in Philadelphia in September:
Is September a good time to visit Philadelphia?
September is a really good time to go to Philadelphia. The weather is nice so plan your packing around outdoor activities and exploring. Check out other good time to visit Philadelphia.
Can you sunbathe in Philadelphia in September?
September is warm in Philadelphia. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.
Is Philadelphia rainy in September?
Philadelphia is often rainy in September. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.
Is it sunny in Philadelphia in September?
Usually, it’s not very sunny in Philadelphia in September, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.
For this page, we’ve looked at the typical weather in Philadelphia, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
