September weather forecastBrookhaven, NY
September
Weather in September
September, the first month of the autumn in Brookhaven, is also an agreeable month, with an average temperature ranging between min 65.3°F (18.5°C) and max 71.4°F (21.9°C).Temperature
In Brookhaven, the average high-temperature in September gently drops from a moderately hot 77.5°F (25.3°C) in August to a pleasant 71.4°F (21.9°C). Brookhaven encounters an average temperature dip to an enjoyable 65.3°F (18.5°C) throughout September, subtly lower than its daytime maximum.Humidity
In September, the average relative humidity is 75%.Rainfall
The months with the least rainfall are January, February and September Rain falls for 12.4 days and accumulates 2.01" (51mm) of rain.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 27min.On the first day of the month, sunrise is at 6:19 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:34 pm EDT.
Sunshine
In September, the average sunshine is 9.1h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum UV index of 5 during September leads to these instructions:
Be vigilant - Preventing sunburn is recommended. When the Sun is at its strongest around midday, find shade and limit exposure. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Brookhaven, NY
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is August (77.5°F).
The month with the lowest average high temperature is January (38.7°F).
- Average low temperature in September: 65.3°F
The months with the highest average low temperature are July and August (71.4°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).
Average pressure in September
Brookhaven, NY
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Brookhaven, NY
- Average wind speed in September: 11.1mph
The windiest month (with the highest average wind speed) is January (14.5mph).
The calmest months (with the lowest average wind speed) are July and August (9.6mph).
Average humidity in September
Brookhaven, NY
- Average humidity in September: 75%
The month with the highest relative humidity is May (80%).
The month with the lowest relative humidity is November (71%).
Average rainfall in September
Brookhaven, NY
- Average rainfall in September: 2.01"
The wettest month (with the highest rainfall) is December (3.31").
The driest months (with the least rainfall) are January, February and September (2.01").
Average rainfall days in September
Brookhaven, NY
- Average rainfall days in September: 12.4 days
The month with the highest number of rainy days is July (16 days).
The month with the least rainy days is February (9 days).
Average snowfall in September
Brookhaven, NY
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.5").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Brookhaven, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (5.4 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Brookhaven, NY
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 9h and 6min
The months with the most sunshine are July and August (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Brookhaven, NY
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is November (17.2 days).
The month with the least sunshine days is February (12.8 days).
Average UV index in September
Brookhaven, NY
- Average UV index in September: 5
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 and December (UV index 2).
Average cloud cover in September
Brookhaven, NY
- Average cloud cover in September: 31
The month with the most cloud cover is December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 26).
Average visibility in September
Brookhaven, NY
- 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).
