September weather forecastSaint Peters, PA
September
Weather in September
The first month of the autumn, September, is still a warm month in Saint Peters, Pennsylvania, with an average temperature varying between 75°F (23.9°C) and 56.5°F (13.6°C).Temperature
The advent of September brings a subtle shift in temperature, with the average high moving from 81.1°F (27.3°C) in August to a still moderately hot 75°F (23.9°C). Saint Peters's average low-temperature is measured at a mild 56.5°F (13.6°C) during September.Humidity
In September, the average relative humidity in Saint Peters is 79%.Rainfall
September is the month with the least rainfall. Rain falls for 12.9 days and accumulates 1.77" (45mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In Saint Peters, the average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:31 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:46 pm EDT.
Sunshine
In Saint Peters, the average sunshine in September is 8.9h.UV index
In Saint Peters, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: A daily high UV index of 4 in September leads to these guidelines:
Act with care - Obligation to protect against skin and eye damage is highlighted. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Saint Peters, PA
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (35.2°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (22.8°F).
Average pressure in September
Saint Peters, 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
Saint Peters, PA
- Average wind speed in September: 5.4mph
The windiest months (with the highest average wind speed) are January and March (8.3mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Saint Peters, PA
- Average humidity in September: 79%
The months with the highest relative humidity are February and October (81%).
The month with the lowest relative humidity is April (76%).
Average rainfall in September
Saint Peters, PA
- Average rainfall in September: 1.77"
The wettest month (with the highest rainfall) is August (2.83").
The driest month (with the least rainfall) is September (1.77").
Average rainfall days in September
Saint Peters, PA
- Average rainfall days in September: 12.9 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (9.4 days).
Average snowfall in September
Saint Peters, PA
- Average snowfall in September: 0"
The month with the highest snowfall is March (3.03").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Saint Peters, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Saint Peters, PA
- Average daylight in September: 12h and 24min
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 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
Saint Peters, PA
- Average sunshine days in September: 15.2 days
The month with the most sunshine days is November (17.8 days).
The month with the least sunshine days is May (11.6 days).
Average UV index in September
Saint Peters, PA
- Average UV index in September: 4
The months with the highest UV index are May, June and July (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
Saint Peters, PA
- Average cloud cover in September: 38
The months with the most cloud cover are February and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Saint Peters, PA
- Average visibility in September: 5mi
The months with the highest visibility are January, March, April, June, July, August, November and December (6mi).
The months with the lowest visibility are February, May, September and October (5mi).
