Long Island, NY Climate

Average Monthly Temperatures and Precipitation

Sunset near Cold Spring Harbor
••• Benson Kua/Flickr/CC BY-SA 2.0

Long Island, New York, is divided into two counties: Nassau to the west, and Suffolk County on the eastern flank of the island (not counting Brooklyn and Queens, which are geographically part of Long Island, but politically party of New York City. Both are on the eastern flank of the Island) The beach-fringed island has four seasons: winter, spring, summer and fall, with hot, sunny summers and chilly, snowy winters.

Below are the average temperatures for Long Island's two counties according to the Northeast Regional Climate Center at Cornell University.

Please remember that these are average temperatures, and the weather can, and does, get hotter in the summer and colder than these monthly averages.

Nassau County Average Temperatures
Weather is recorded at Nassau County's Mineola, NY weather station.

  • January - 31.9 degrees Fahrenheit/-0.05 Celsius
  • February - 33.4 F./7 C.
  • March - 41.1 F./5.05 C.
  • April - 49.7 F./ 9.8 C.
  • May - 59.5 F./ 15.2 C.
  • June 68.7 F./20.3 C.
  • July - 74.2 F./23.4 C.
  • August - 72.8 F./22.6 C.
  • September - 65.5 F./18.6 C.
  • October - 55 F./12.7 C.
  • November - 46.2 F./7.8 C.
  • December 36.6 F./2.5 C.

Suffolk County Average Temperatures
Weather is recorded at Suffolk County's Long Island MacArthur Airport, Islip, NY.

  • January - 30.9 degrees Fahrenheit/-0.6 C.
  • February - 32.4 F./0.2 C.
  • March - 39.8 F./4.3 C.
  • April - 49.1 F./9.5 C.
  • May - 52.2 F./11.2 C.
  • June 68.5 f./20.2 C.
  • July - 74.6 F./23.6 C.
  • August - 73.1 F./22.8 C.
  • September - 65.8 F./18.7 C.
  • October - 54.3 F./12.3 C.
  • November - 44.9 F./7.1 C.
  • December - 35.7 F./2 C.

Nassau County Average Precipitation​​
Weather is recorded at Nassau County's Mineola, NY weather station.

  • January - 4.01"
  • February - 2.96"
  • March - 4.28"
  • April - 4.26"
  • May - 4"
  • June 3.66"
  • July - 3.88"
  • August - 3.74"
  • September - 3.98"
  • October - 3.53"
  • November - 4"
  • December 3.80"

Suffolk County Average Precipitation​
Weather is recorded at Suffolk County's Long Island MacArthur Airport, Islip, NY.

  • January - 4.27"
  • February - 3.33"
  • March - 4.76"
  • April - 4.13"
  • May - 3.90"
  • June 3.71"
  • July - 2.93"
  • August - 4.48"
  • September - 3.39"
  • October - 3.63"
  • November - 3.86
  • December - 4.13"