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
Weather in September
Temperature
As September commences, the average high-temperature subtly reduces, transitioning from 81.1°F (27.3°C) in August to a still moderately hot 75°F (23.9°C). Throughout September, Downingtown witnesses a nighttime temperature average of 57.7°F (14.3°C).Humidity
In Downingtown, the average relative humidity in September is 79%.Rainfall
In September, the rain falls for 12.5 days. Throughout September, 1.89" (48mm) of precipitation is accumulated. In Downingtown, during the entire year, the rain falls for 145.6 days and collects up to 26.81" (681mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 6:31 am and sunset at 7:33 pm. On the last day of September, in Downingtown, sunrise is at 6:58 am and sunset at 6:46 pm EDT.
Sunshine
In September, the average sunshine is 8.7h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: The UV index of 4 during September leads to these advisories:
Preventative actions are necessary - Recommendations to ward off sunburn are given. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Experience reduced UV exposure by about half when donning a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September in Downingtown?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Downingtown, PA
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (35.4°F).
- Average low temperature in September: 57.7°F
The month with the highest average low temperature is July (66.2°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).
Average pressure in September
Downingtown, PA
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Downingtown, PA
- Average wind speed in September: 5.6mph
The windiest months (with the highest average wind speed) are January and March (8.5mph).
The calmest months (with the lowest average wind speed) are July and August (5.2mph).
Average humidity in September
Downingtown, PA
- Average humidity in September: 79%
The months with the highest relative humidity are February, May and October (80%).
The month with the lowest relative humidity is April (75%).
Average rainfall in September
Downingtown, PA
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is August (3.31").
The driest month (with the least rainfall) is February (1.61").
Average rainfall days in September
Downingtown, PA
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (6.7 days).
Average snowfall in September
Downingtown, PA
- Average snowfall in September: 0"
The month with the highest snowfall is March (3.46").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Downingtown, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Downingtown, 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 4min
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 36min).
Average sunshine days in September
Downingtown, PA
- Average sunshine days in September: 16.3 days
The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is May (12.3 days).
Average UV index in September
Downingtown, PA
- Average UV index in September: 4
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, March, November and December (UV index 2).
Average cloud cover in September
Downingtown, PA
- Average cloud cover in September: 39
The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in September
Downingtown, PA
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).
Downingtown, Pennsylvania, USA
Weather forecast for your location
2. Allow the app to use your location