September weather forecast and climate
West Islip, NY

The first month of the autumn, September, is still a pleasant month in West Islip, New York, with average temperature varying between 72.3°F (22.4°C) and 65.5°F (18.6°C).

Temperature

In September, the average high-temperature slightly decreases, from a moderately hot 78.4°F (25.8°C) in August, to a pleasant 72.3°F (22.4°C). In West Islip, in September, the average low-temperature is 65.5°F (18.6°C).

Humidity

In West Islip, the average relative humidity is 74%.

Rainfall

In West Islip, during 13.8 rainfall days, 2.56" (65mm) of precipitation is typically accumulated. Throughout the year, in West Islip, there are 157 rainfall days, and 35.98" (914mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall in West Islip.

Daylight

The average length of the day in September is 12.4h.

Sunshine

In West Islip, New York, the average sunshine in September is 9.1h.

UV index

The average daily maximum UV index in West Islip is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to the UV radiation for ordinary individuals.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions - Protection against the skin and eye damage is obliged. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. 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.

What is the temperature in September in West Islip?

The average high-temperature, in September, is 72.3°F (22.4°C), while the average low-temperature is 65.5°F (18.6°C).

What is the average humidity in September in West Islip?

The average relative humidity in September in West Islip, New York, is 74%.

How much does it rain in West Islip in September?

In West Islip, New York, in September, it is raining for 13.8 days, with typically 2.56" (65mm) of accumulated precipitation.

Does it snow in West Islip in September?

In West Islip, in September, it doesn't snow. In October, it regularly snows.

When it does not snow in West Islip?

In West Islip snow does not fall in May through September.

What is the average length of the day in September in West Islip?

In West Islip, New York, the average length of the day in September is 12.4h.

How many hours of sunshine does West Islip have in September?

In September, the average sunshine in West Islip, New York, is 9.1h.

How high is the UV index in September in West Islip?

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium hazard to health from the exposure to the Sun's UV radiation.
Average temperature in September - West Islip, NY
  • Average high temperature in September: 72.3°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: 65.5°F

Months with the highest average low temperature are July and August (72°F).
The coldest month (with the lowest average low temperature) is January (30.4°F).

Average pressure in September - West Islip, NY
  • Average pressure in September: 30.05"

The month with the highest atmospheric pressure is November (30.09").
The month with the lowest atmospheric pressure is June (29.93").

Average wind speed in September - West Islip, NY
  • Average wind speed in September: 10.3mph

The windiest month (with the highest average wind speed) is January (13.6mph).
The calmest month (with the lowest average wind speed) is July (8.9mph).

Average humidity in September - West Islip, NY
  • Average humidity in September: 74%

The month with the highest relative humidity is May (78%).
The month with the lowest relative humidity is November (71%).

Average rainfall in September - West Islip, NY
  • Average rainfall in September: 2.56"

The wettest month (with the highest rainfall) is July (3.98").
The driest month (with the least rainfall) is January (2.2").

Average rainfall days in September - West Islip, NY
  • Average rainfall days in September: 13.8 days

The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is January (8.1 days).

Average snowfall in September - West Islip, NY
  • Average snowfall in September: 0"

The month with the highest snowfall is March (2.17").
Months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September - West Islip, NY
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (4.2 days).
Months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - West Islip, NY
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15.1h).
The month with the shortest days is December (Average daylight: 9.3h).

  • Average sunshine in September: 9.1h

The month with the most sunshine is July (Average sunshine: 10.8h).
The month with the least sunshine is February (Average sunshine: 4.8h).

Average sunshine days in September - West Islip, NY
  • Average sunshine days in September: 14.6 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is July (11.4 days).

Average UV index in September - West Islip, NY
  • Average UV index in September: 5

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, March and December (UV index 2).

Average cloud cover in September - West 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 - West Islip, NY
  • Average visibility in September: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).