September weather forecastPetersham, MA
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Petersham, Massachusetts, with temperature in the range of an average high of 71.2°F (21.8°C) and an average low of 52.2°F (11.2°C).Temperature
With the arrival of September, Petersham experiences a modest decline in average high-temperatures, transitioning from a moderately hot 78.4°F (25.8°C) in August to an agreeable 71.2°F (21.8°C). Petersham witnesses an average low-temperature of 52.2°F (11.2°C) throughout the month of September.Humidity
In September, the average relative humidity is 79%.Rainfall
September is the month with the least rainfall. Rain falls for 11.9 days and accumulates 1.77" (45mm) of precipitation.Snowfall
In Petersham, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 29min.On the first day of September, sunrise is at 6:14 am and sunset at 7:22 pm. On the last day of the month, sunrise is at 6:45 am and sunset at 6:31 pm EDT.
Sunshine
The average sunshine in September is 8.4h.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 unsafe exposure to UV radiation for ordinary individuals.Note: In September, the UV index of 4 transforms into the following advice:
Undertake precautions - It is suggested to shield oneself from sunburn. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Petersham, MA
- Average high temperature in September: 71.2°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.5°F).
- Average low temperature in September: 52.2°F
The month with the highest average low temperature is July (59.9°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).
Average pressure in September
Petersham, MA
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Petersham, MA
- Average wind speed in September: 5.6mph
The windiest months (with the highest average wind speed) are January, February and March (8.1mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Petersham, MA
- Average humidity in September: 79%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is April (73%).
Average rainfall in September
Petersham, MA
- Average rainfall in September: 1.77"
The wettest month (with the highest rainfall) is October (2.8").
The driest month (with the least rainfall) is September (1.77").
Average rainfall days in September
Petersham, MA
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is May (15.6 days).
The month with the least rainy days is January (7.4 days).
Average snowfall in September
Petersham, MA
- Average snowfall in September: 0"
The month with the highest snowfall is February (6.69").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Petersham, MA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (10.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Petersham, MA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 24min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days in September
Petersham, MA
- Average sunshine days in September: 15.2 days
The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is June (13 days).
Average UV index in September
Petersham, MA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Petersham, MA
- Average cloud cover in September: 39
The months with the most cloud cover are February and March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 35).
Average visibility in September
Petersham, MA
- Average visibility in September: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October, November and December (5mi).





