United StatesAverage weather for Long Island in September
It's pleasantly warm in September in Long Island with an average temperature of 22°C. Temperatures this month range from a low of 17°C to a high of 25°C. At night, you can expect temperatures between 9°C and 16°C.
Start of September
The month of September starts in Long Island with warm temps, averaging around 24°C during the day and nights around 15°C. You can expect regular precipitation, but there will also be some sunny days in the early part of the month.
Mid September
By mid-September, daytime temps drop to around 23°C, with nights around 13°C. There’s a chance of some showers during this time, but plenty of dry and sunny days too.
End of September
By the end of September, the average daytime temperature in Long Island is around 22°C, while nighttime temps are about 12°C. A shower might pop up, but overall, the weather will be dry and sunny.
Water temperature
The water temperature at Long Island is 18°C this month. You can swim, but it's a bit chilly.
In September, there is an average of 110 mm of precipitation, spread over 7 days. The wind speed is around 4 Bft, mostly coming from the South.
Long Island in September |
New York | ||
|---|---|---|---|
 Average temperature |
22°C | 27°C | |
 Max. temperature |
25°C | 31°C | |
| Min. temperature |
17°C | -5°C | |
 Total precipitation |
110 mm | 57 mm | |
| Rainy days |
7 days | 9 days | |
August
UV index
The UV index is a maximum of 7 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is September a good time to visit Long Island?
Looking for sun? September isn’t a good month to be in Long Island. The temperature is nice, but there’s too much chance of rain.
Temperature records
With 33°C in 2015, Long Island reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 12°C in 2018. The extreme nighttime temperatures ranged from a lowest recorded value of 1°C to a highest value of 22°C.
Check out the climate of Long Island for all months and discover the best travel time
Daily Temperature in September in Long Island
This chart shows the average daily high and low temperatures in September for Long Island, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.
Daily Precipitation in September in Long Island
The chart below shows the average daily precipitation in September for Long Island, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for September, you can expect about 7 days of precipitation in Long Island.
Daily UV index in September in Long Island
This chart shows the average daily UV index in September in Long Island, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in Long Island over the years
This chart shows the average temperature in September in Long Island, measured in degrees Celsius, over the past few years.
Total precipitation in September in Long Island over the years
This chart shows the average precipitation in September in Long Island, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.
Daily weather in September for Long Island
Click on any day in September to get detailed info about the usual weather on that day in Long Island. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Long Island
Have you been to Long Island in September?
Share your weather experience in September in Long Island.
Average weather in Long Island by month
Click on a month below to see detailed weather info for Long Island. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
Or check out the climate of Long Island for all months at once
