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
September ushers in a minute temperature change, with average high-temperatures reducing from August's moderately hot 83.3°F (28.5°C) to a still warm 76.1°F (24.5°C). An average minimum temperature of 59°F (15°C) is recorded during the month of September.Humidity
In Norristown, the average relative humidity in September is 76%.Rainfall
In Norristown, in September, during 10.8 rainfall days, 0.98" (25mm) of precipitation is typically accumulated. In Norristown, during the entire year, the rain falls for 138.2 days and collects up to 15.59" (396mm) of precipitation.Snowfall
In Norristown, snow does not fall in April, June through November.Daylight
In Norristown, the average length of the day in September 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
In September, the average sunshine is 8.8h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: In September, a daily UV index of 4 turns into the following recommendations:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Norristown in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow in Norristown?
How many hours of daylight does Norristown have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Norristown have in September?
How high is the UV index in September?
Average temperature in September
Norristown, PA
- Average high temperature in September: 76.1°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 (36.7°F).
- Average low temperature in September: 59°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in September
Norristown, PA
- Average pressure in September: 30.06"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
Norristown, PA
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest months (with the lowest average wind speed) are July and August (5.3mph).
Average humidity in September
Norristown, PA
- Average humidity in September: 76%
The months with the highest relative humidity are February and October (79%).
The months with the lowest relative humidity are April and July (72%).
Average rainfall in September
Norristown, PA
- Average rainfall in September: 0.98"
The wettest month (with the highest rainfall) is July (1.89").
The driest month (with the least rainfall) is February (0.91").
Average rainfall days in September
Norristown, PA
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is May (16 days).
The month with the least rainy days is November (7.4 days).
Average snowfall in September
Norristown, PA
- Average snowfall in September: 0"
The months with the highest snowfall are February and March (0.55").
The months with the least snowfall are April, June, July, August, September, October and November (0").
Average snowfall days in September
Norristown, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.2 days).
The months with the least snowfall days are April, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Norristown, 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 48min).
Average sunshine days in September
Norristown, PA
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is November (20.5 days).
The months with the least sunshine days are May and June (12.8 days).
Average UV index in September
Norristown, 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
Norristown, PA
- Average cloud cover in September: 38
The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in September
Norristown, 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).
Norristown, Pennsylvania, USA
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