September weather forecastCohasset, MA
September
Weather in September
September, the first month of the autumn in Cohasset, is also an agreeable month, with temperature in the range of an average high of 71.4°F (21.9°C) and an average low of 58.1°F (14.5°C).Temperature
The onset of September is marked by a minor decrease in temperature, transitioning from a moderately hot 78.4°F (25.8°C) in August to a pleasant 71.4°F (21.9°C). The nighttime temperature dips to a mild 58.1°F (14.5°C) on average during September.Humidity
The months with the highest humidity are February, June and September, with an average relative humidity of 77%.Rainfall
September is the month with the least rainfall in Cohasset. Rain falls for 11.7 days and accumulates 1.5" (38mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:09 am and sunset at 7:16 pm. On the last day of September, sunrise is at 6:39 am and sunset at 6:26 pm EDT.
Sunshine
The average sunshine in September is 8.5h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the ordinary person.Note: An average UV index of 4 in September transforms into this advice:
Act with care - The suggestion to avoid sunburn is emphasized. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Cohasset, MA
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is January (34.5°F).
- Average low temperature in September: 58.1°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in September
Cohasset, MA
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Cohasset, MA
- Average wind speed in September: 7.7mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest month (with the lowest average wind speed) is August (6.9mph).
Average humidity in September
Cohasset, MA
- Average humidity in September: 77%
The months with the highest relative humidity are February, June and September (77%).
The month with the lowest relative humidity is April (72%).
Average rainfall in September
Cohasset, MA
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is December (3.11").
The driest month (with the least rainfall) is September (1.5").
Average rainfall days in September
Cohasset, MA
- Average rainfall days in September: 11.7 days
The month with the highest number of rainy days is July (16.5 days).
The month with the least rainy days is January (8.6 days).
Average snowfall in September
Cohasset, MA
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.86").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Cohasset, MA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Cohasset, 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 12min).
- Average sunshine in September: 8h and 30min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 48min).
Average sunshine days in September
Cohasset, MA
- Average sunshine days in September: 15.5 days
The month with the most sunshine days is November (17 days).
The month with the least sunshine days is July (12.8 days).
Average UV index in September
Cohasset, MA
- Average UV index in September: 4
The months with the highest UV index are 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
Cohasset, MA
- Average cloud cover in September: 34
The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Cohasset, MA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
