September weather forecastWinterstown, PA
September
Weather in September
The first month of the autumn, September, is still a warm month in Winterstown, Pennsylvania, with an average temperature fluctuating between 57.2°F (14°C) and 75°F (23.9°C).Temperature
September brings a slight decrease in temperature, down from 81°F (27.2°C) in August to a still warm 75°F (23.9°C). Winterstown experiences an average temperature drop to a mild 57.2°F (14°C) during September nights.Humidity
In Winterstown, the average relative humidity in September is 79%.Rainfall
In Winterstown, in September, during 12.1 rainfall days, 1.61" (41mm) of precipitation is typically accumulated. Throughout the year, there are 139.8 rainfall days, and 22.95" (583mm) of precipitation is accumulated.Snowfall
In Winterstown, snow does not fall in June through September.Daylight
In September, the average length of the day in Winterstown is 12h and 26min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:37 pm. On the last day of September, sunrise is at 7:02 am and sunset at 6:50 pm EDT.
Sunshine
The average sunshine in September is 8.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the average person.Note: The daily high UV index of 4 during September translates into the following recommendations:
Undertake precautions - Obligation exists to protect against skin and eye damage. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at 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
Average temperature in September
Winterstown, PA
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (35.8°F).
- Average low temperature in September: 57.2°F
The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).
Average pressure in September
Winterstown, PA
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Winterstown, PA
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is March (8.9mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in September
Winterstown, PA
- Average humidity in September: 79%
The month with the highest relative humidity is May (81%).
The months with the lowest relative humidity are March, April and November (76%).
Average rainfall in September
Winterstown, PA
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is August (2.8").
The driest month (with the least rainfall) is February (1.26").
Average rainfall days in September
Winterstown, PA
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is May (15.9 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Winterstown, PA
- Average snowfall in September: 0"
The month with the highest snowfall is March (3.23").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Winterstown, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Winterstown, PA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 8h and 54min
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 42min).
Average sunshine days in September
Winterstown, PA
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is January (20.4 days).
The month with the least sunshine days is May (11.7 days).
Average UV index in September
Winterstown, 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, November and December (UV index 2).
Average cloud cover in September
Winterstown, PA
- Average cloud cover in September: 37
The months with the most cloud cover are February and March (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Winterstown, 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).
