September weather forecastRoslyn, NY
September
Weather in September
September, the first month of the autumn in Roslyn, is still a warm month, with an average temperature fluctuating between 73.4°F (23°C) and 63.5°F (17.5°C).Temperature
September marks a gentle change in average high-temperature, declining from August's 80.4°F (26.9°C) to a still moderately hot 73.4°F (23°C). Roslyn experiences a steady low-temperature of 63.5°F (17.5°C) throughout September.Humidity
In Roslyn, the average relative humidity in September is 73%.Rainfall
The month with the least rainfall is September, when the rain falls for 12.9 days and typically collects 2.4" (61mm) of precipitation.Snowfall
In Roslyn, snow does not fall in May through October.Ocean temperature
In Roslyn, New York, in September, the average water temperature is 70.2°F (21.2°C).Note: Most people do not take pleasure in swimming in water at 70.2°F (21.2°C). The difficulty of managing breathing increases as the water temperature dips from 69.8°F (21°C) to 59°F (15°C).
Daylight
In September, the average length of the day in Roslyn is 12h and 27min.On the first day of September, 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
The average sunshine in September in Roslyn is 9h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for the average person.Note: In September, a regular UV index of 5 translates into these guidelines:
Act with care - The suggestion to avoid sunburn is emphasized. When the Sun is at its strongest around midday, find shade and limit exposure. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The mirror effect of sand and water ups the UV radiation strength.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Roslyn, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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).
