September weather forecastRoslyn Harbor, NY
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Roslyn Harbor, New York, with an average temperature varying between 73.4°F (23°C) and 63.5°F (17.5°C).Temperature
A modest decline in the average high-temperature is seen during September, decreasing from a warm 80.4°F (26.9°C) in August to a still moderately hot 73.4°F (23°C). During the nights in September, Roslyn Harbor experiences a consistent average temperature of 63.5°F (17.5°C).Humidity
The average relative humidity in September is 73%.Rainfall
September is the month with the least rainfall in Roslyn Harbor. Rain falls for 12.9 days and accumulates 2.4" (61mm) of precipitation.Snowfall
In Roslyn Harbor, snow does not fall in May through October.Ocean temperature
In September, the average ocean temperature in Roslyn Harbor is 70.2°F (21.2°C).Note: For most, swimming in 70.2°F (21.2°C) is not a pleasant activity. Breathing becomes increasingly challenging as water temperature descends from 69.8°F (21°C) to 59°F (15°C).
Daylight
The average length of the day in September in Roslyn Harbor is 12h and 27min.On the first day of September in Roslyn Harbor, sunrise is at 6:22 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 6:37 pm EDT.
Sunshine
In Roslyn Harbor, New York, the average sunshine in September is 9h.UV index
In September, the average daily maximum UV index in Roslyn Harbor is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Make use of precautions - It is urged to ward off sun damage. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Caution! Sand and water surfaces escalate the UV intensity from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Roslyn Harbor, NY
- Average high temperature in September: 73.4°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (36.5°F).
- Average low temperature in September: 63.5°F
The months with the highest average low temperature are July and August (70.3°F).
The coldest month (with the lowest average low temperature) is January (27.3°F).
Average pressure in September
Roslyn Harbor, NY
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Roslyn Harbor, NY
- Average wind speed in September: 8.3mph
The windiest month (with the highest average wind speed) is January (11.2mph).
The calmest month (with the lowest average wind speed) is July (7.3mph).
Average humidity in September
Roslyn Harbor, NY
- Average humidity in September: 73%
The months with the highest relative humidity are February, May and December (75%).
The months with the lowest relative humidity are August and November (71%).
Average rainfall in September
Roslyn Harbor, NY
- Average rainfall in September: 2.4"
The wettest month (with the highest rainfall) is December (4.06").
The driest month (with the least rainfall) is September (2.4").
Average rainfall days in September
Roslyn Harbor, NY
- Average rainfall days in September: 12.9 days
The month with the highest number of rainy days is July (17.9 days).
The month with the least rainy days is January (9.3 days).
Average snowfall in September
Roslyn Harbor, NY
- Average snowfall in September: 0"
The month with the highest snowfall is March (2.01").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Roslyn Harbor, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average sea temperature in September
Roslyn Harbor, NY
- Average sea temperature in September: 70.1°F
The best month for swimming (with the highest average sea temperature) is August (74.1°F).
The coldest month (with the lowest average sea temperature) is February (39.9°F).
Average daylight in September /
Average sunshine in September
Roslyn Harbor, 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 0min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Roslyn Harbor, NY
- Average sunshine days in September: 15.2 days
The month with the most sunshine days is November (18 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in September
Roslyn Harbor, 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, November and December (UV index 2).
Average cloud cover in September
Roslyn Harbor, NY
- Average cloud cover in September: 33
The months with the most cloud cover are February and December (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 29).
Average visibility in September
Roslyn Harbor, 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).
