September weather forecastBrookline, MA
September
Weather in September
September in Brookline signals the advent of autumn, with subtle shifts in temperature and a perceptible drop in sunshine hours. The average highest temperature falls decently from 80.4°F (26.9°C) in August down to 72.9°F (22.7°C), hinting at the incoming fall. Despite the temperature drop, September retains a fair share of summer's warmth. With leaves changing color and a noticeable chill in the early morning and late evening air, autumn's arrival becomes unmistakable. The scenic beauty of Brookline in September aligns with the charm of the fall season.Temperature
The start of September signals a gentle decrease in the average high-temperature, transitioning from a moderately hot 80.4°F (26.9°C) in August to a pleasant 72.9°F (22.7°C). Throughout the month of September, Brookline witnesses an average low-temperature of 56.7°F (13.7°C).Humidity
In Brookline, the average relative humidity in September is 75%.Rainfall
September is the month with the least rainfall. Rain falls for 6.4 days and accumulates 0.2" (5mm) of precipitation.Snowfall
In Brookline, snow does not fall in June through October.Daylight
The average length of the day in September in Brookline is 12h and 28min.On the first day of September, sunrise is at 6:10 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:27 pm EDT.
Sunshine
In September, the average sunshine is 8.5h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: The UV index of 4 in September translates into these instructions:
Guard yourself - Avoiding sunburn is suggested. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Brookline, MA
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (33.8°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in September
Brookline, 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
Brookline, MA
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in September
Brookline, MA
- Average humidity in September: 75%
The months with the highest relative humidity are January and February (77%).
The month with the lowest relative humidity is April (69%).
Average rainfall in September
Brookline, MA
- Average rainfall in September: 0.2"
The wettest month (with the highest rainfall) is November (0.63").
The driest month (with the least rainfall) is September (0.2").
Average rainfall days in September
Brookline, MA
- Average rainfall days in September: 6.4 days
The month with the highest number of rainy days is July (9.6 days).
The month with the least rainy days is January (4.3 days).
Average snowfall in September
Brookline, MA
- Average snowfall in September: 0"
The month with the highest snowfall is December (0.71").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in September
Brookline, MA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Brookline, 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 30min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in September
Brookline, MA
- Average sunshine days in September: 21.8 days
The month with the most sunshine days is January (23.5 days).
The month with the least sunshine days is June (17.4 days).
Average UV index in September
Brookline, MA
- Average UV index in September: 4
The months with the highest UV index are 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
Brookline, MA
- Average cloud cover in September: 36
The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Brookline, 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).
