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 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
September
Weather in September
Temperature
The onset of September brings a small shift in high-temperatures, falling from 83.5°F (28.6°C) in August to a still moderately hot 76.6°F (24.8°C). During the nights in September, an average low-temperature of 60.8°F (16°C) is observed.Humidity
In Swarthmore, the average relative humidity in September is 76%.Rainfall
In Swarthmore, Pennsylvania, in September, during 12.6 rainfall days, 1.73" (44mm) of precipitation is typically accumulated. In Swarthmore, during the entire year, the rain falls for 148.4 days and collects up to 25.94" (659mm) of precipitation.Snowfall
In Swarthmore, 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 6:29 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
The average sunshine in September is 8.9h.UV index
In Swarthmore, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.Note: A maximum daily UV index of 5 during September morphs into the following directions:
Take precautions - Protection against sunburn is recommended. It's recommended to limit sun exposure when its radiation is at its peak during midday. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
How many hours of daylight does Swarthmore have in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Swarthmore have in September?
What is the UV index reading in September?
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).
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).
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).
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%).
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").
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).
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").
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).
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).
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).
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).
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).
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).