September weather forecastIslip, NY
September
Weather in September
September, the first month of the autumn in Islip, is still a pleasant month, with an average temperature ranging between min 65.3°F (18.5°C) and max 72.1°F (22.3°C).Temperature
As September begins, there is a minor decrease in the average high-temperature, softly falling from a warm 78.4°F (25.8°C) in August to an agreeable 72.1°F (22.3°C). During September, Islip's nighttime temperatures demonstrate a subtle cooling from daytime highs, stabilizing at an enjoyable 65.3°F (18.5°C).Humidity
In Islip, the average relative humidity in September is 74%.Rainfall
In September, the rain falls for 13.5 days. Throughout September, 2.56" (65mm) of precipitation is accumulated. Throughout the year, there are 153.2 rainfall days, and 34.45" (875mm) of precipitation is accumulated.Snowfall
In Islip, snow does not fall in April through September.Ocean temperature
In Islip, in September, the average water temperature is 69.6°F (20.9°C).Note: For the majority of people, swimming in water at 69.6°F (20.9°C) is not enjoyable. The challenge of controlling breathing escalates as the temperature decreases from 69.8°F (21°C) to 59°F (15°C).
Daylight
In September, the average length of the day is 12h and 27min.On the first day of the month, sunrise is at 6:20 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:36 pm EDT.
Sunshine
In September, the average sunshine in Islip is 9.1h.UV index
The average daily maximum UV index in September in Islip is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In September, a daily UV index of 5 turns into the following recommendations:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Islip, NY
- Average high temperature in September: 72.1°F
The warmest month (with the highest average high temperature) is July (79°F).
The month with the lowest average high temperature is January (37.9°F).
- Average low temperature in September: 65.3°F
The month with the highest average low temperature is August (72°F).
The coldest month (with the lowest average low temperature) is January (30°F).
Average pressure in September
Islip, 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
Islip, NY
- Average wind speed in September: 10.1mph
The windiest month (with the highest average wind speed) is January (13.4mph).
The calmest month (with the lowest average wind speed) is July (8.6mph).
Average humidity in September
Islip, NY
- Average humidity in September: 74%
The months with the highest relative humidity are May and June (77%).
The month with the lowest relative humidity is November (71%).
Average rainfall in September
Islip, NY
- Average rainfall in September: 2.56"
The wettest month (with the highest rainfall) is July (3.86").
The driest month (with the least rainfall) is January (2.05").
Average rainfall days in September
Islip, NY
- Average rainfall days in September: 13.5 days
The month with the highest number of rainy days is July (17.9 days).
The month with the least rainy days is January (7.6 days).
Average snowfall in September
Islip, NY
- Average snowfall in September: 0"
The month with the highest snowfall is March (1.97").
The months with the least snowfall are April, May, June, July, August and September (0").
Average snowfall days in September
Islip, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in September
Islip, NY
- Average sea temperature in September: 69.6°F
The best month for swimming (with the highest average sea temperature) is August (74°F).
The coldest month (with the lowest average sea temperature) is February (39.7°F).
Average daylight in September /
Average sunshine in September
Islip, NY
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 9h and 6min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Islip, NY
- Average sunshine days in September: 14.7 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is July (11.2 days).
Average UV index in September
Islip, 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
Islip, NY
- Average cloud cover in September: 31
The month with the most cloud cover is December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Islip, 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).
