September weather forecast
Chester, PA

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Weather in September

September marks a significant change in Chester's climate as temperatures begin to cool. A drop in rainfall to 1.73" (44mm) signifies the arrival of early autumn. The city eagerly welcomes autumn as the leaves begin to change color, offering a spectacular canvas of hues. With the hustle of summer over, Chester eases into the calm serenity of fall.

Temperature

The advent of September brings a subtle shift in temperature, with the average high moving from a moderately hot 83.5°F (28.6°C) in August to a still warm 76.6°F (24.8°C). Chester's nights in September cool down to an average low-temperature of 60.8°F (16°C).

Humidity

In September, the average relative humidity is 76%.

Rainfall

In Chester, during September, the rain falls for 12.6 days and regularly aggregates up to 1.73" (44mm) of precipitation. Throughout the year, there are 148.4 rainfall days, and 25.94" (659mm) of precipitation is accumulated.

Snowfall

In Chester, snow does not fall in June through October.

Daylight

In September, the average length of the day is 12h and 26min.
On the first day of the month, sunrise is at 6:30 am and sunset at 7:32 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:44 pm EDT.

Sunshine

In Chester, the average sunshine in September is 8.9h.

UV index

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for average individuals.
Note: In September, the maximum UV index of 5 suggests these recommendations:
Take necessary precautions - Suggestions to elude sunburn are provided. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Updated: Aug 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

The average high-temperature and low-temperature during September are 76.6°F (24.8°C) and 60.8°F (16°C) respectively. In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 89.6°F (32°C).

What is the average humidity in September?

The average relative humidity in September is 76%.

How many days does it rain in September?

In Chester, in September, it is raining for 12.6 days, with typically 1.73" (44mm) of accumulated precipitation.

When it does not snow?

In Chester, snow does not fall in June through October.

How many hours of daylight does Chester have in September?

The average day length in September is 12h and 26min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:30 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.

How many hours of sunshine does Chester have in September?

In Chester, the average sunshine duration in September is 8.9h.

What is the UV index intensity in September?

In Chester, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health threat from unprotected exposure to 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
Chester, PA

Average temperature in September - Chester, PA
  • Average high temperature in September: 76.6°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 (37.4°F).

  • Average low temperature in September: 60.8°F

The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).

Average pressure in September
Chester, PA

Average pressure in September - Chester, 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
Chester, PA

Average wind speed in September - Chester, PA
  • Average wind speed in September: 5.9mph

The windiest month (with the highest average wind speed) is March (8.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

Average humidity in September
Chester, PA

Average humidity in September - Chester, PA
  • Average humidity in September: 76%

The months with the highest relative humidity are February, October and December (77%).
The month with the lowest relative humidity is April (71%).

Average rainfall in September
Chester, PA

Average rainfall in September - Chester, PA
  • Average rainfall in September: 1.73"

The wettest month (with the highest rainfall) is August (3.11").
The driest month (with the least rainfall) is January (1.61").

Average rainfall days in September
Chester, PA

Average rainfall days in September - Chester, PA
  • Average rainfall days in September: 12.6 days

The month with the highest number of rainy days is July (17 days).
The month with the least rainy days is January (7.1 days).

Average snowfall in September
Chester, PA

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

The month with the highest snowfall is March (2.32").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in September
Chester, PA

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

The month with the highest number of snowfall days is February (3.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Chester, PA

Average daylight in September / Average sunshine in September - Chester, 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 42min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).

Average sunshine days in September
Chester, PA

Average sunshine days in September - Chester, PA
  • Average sunshine days in September: 15.5 days

The month with the most sunshine days is January (20.8 days).
The month with the least sunshine days is July (11.3 days).

Average UV index in September
Chester, PA

Average UV index in September - Chester, 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
Chester, PA

Average cloud cover in September - Chester, PA
  • Average cloud cover in September: 37

The month with the most cloud cover is February (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 30).

Average visibility in September
Chester, PA

Average visibility in September - Chester, 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).

Chester, Pennsylvania, USA

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