September weather forecast
Swarthmore, PA

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Swarthmore, Pennsylvania, with an average temperature fluctuating between 76.6°F (24.8°C) and 60.8°F (16°C).

Temperature

As September begins, there is a minor decrease in the average high-temperature, softly falling from 83.5°F (28.6°C) in August to a still moderately hot 76.6°F (24.8°C). The average nighttime temperature in Swarthmore lowers to a refreshing 60.8°F (16°C) throughout September.

Humidity

The average relative humidity in September is 76%.

Rainfall

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

Snowfall

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

Daylight

The average length of the day in September in Swarthmore is 12h and 26min.
On the first day of the month, sunrise is at 6:29 am and sunset at 7:32 pm. On the last day of September, in Swarthmore, Pennsylvania, sunrise is at 6:57 am and sunset at 6:44 pm EDT.

Sunshine

The average sunshine in September in Swarthmore 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 rays for ordinary individuals.
Note: During September, 5 as the daily maximum UV index converts into the following advice:
Ensure safety - Imperative it is to shield skin and eyes from damage. It's recommended to limit sun exposure when its radiation is at its peak during midday. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
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Frequently asked questions

What is the average September temperature in Swarthmore?

The high-temperature, in September, in Swarthmore, records 76.6°F (24.8°C), while the low-temperature is 60.8°F (16°C). In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines air temperature and relative humidity, is estimated at 89.6°F (32°C).

What is the average humidity in September in Swarthmore?

In Swarthmore, the average relative humidity in September is 76%.

How much does it rain in Swarthmore in September?

In September, the rain falls for 12.6 days. Throughout September, 1.73" (44mm) of precipitation is accumulated.

When it does not snow in Swarthmore?

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

What is the average length of the day in September in Swarthmore?

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

When are sunrise and sunset in September in Swarthmore?

In September, on the first day of the month, sunrise is at 6:29 am and sunset at 7:32 pm. On the last day of the month, in Swarthmore, sunrise is at 6:57 am and sunset at 6:44 pm EDT.

How long on average sun shines in September in Swarthmore?

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

What is the UV index intensity in September in Swarthmore?

In September, the average daily maximum UV index in Swarthmore, Pennsylvania, is 5. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to Sun's UV rays.
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
Swarthmore, PA

Average temperature in September - Swarthmore, 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).

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Average pressure in September
Swarthmore, PA

Average pressure in September - Swarthmore, 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).

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Average wind speed in September
Swarthmore, PA

Average wind speed in September - Swarthmore, 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).

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Average humidity in September
Swarthmore, PA

Average humidity in September - Swarthmore, 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%).

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Average rainfall in September
Swarthmore, PA

Average rainfall in September - Swarthmore, 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").

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Average rainfall days in September
Swarthmore, PA

Average rainfall days in September - Swarthmore, 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).

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Average snowfall in September
Swarthmore, PA

Average snowfall in September - Swarthmore, 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").

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Average snowfall days in September
Swarthmore, PA

Average snowfall days in September - Swarthmore, 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).

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

Average daylight in September / Average sunshine in September - Swarthmore, 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).

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Average sunshine days in September
Swarthmore, PA

Average sunshine days in September - Swarthmore, 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).

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Average UV index in September
Swarthmore, PA

Average UV index in September - Swarthmore, 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).

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Average cloud cover in September
Swarthmore, PA

Average cloud cover in September - Swarthmore, 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).

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Average visibility in September
Swarthmore, PA

Average visibility in September - Swarthmore, 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).

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Swarthmore, Pennsylvania, USA

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