Home Weather

Weather

Weather forecast and 7 day planner provided by AccuWeather.com

Weather Forecast | Weather Maps | Weather Radar | Hurricane Center

Northeast US Infrared Satellite

Forecast Heat Index

Current Heat Index

US Infrared Satellite

Daily Forecast

Daily Forecast

Long Island temperatures vary from west to east, with the western part of the island warmer on most occasions than the east. This is due to two factors: one because the western part is closer to the mainland and the other is the western part is more developed causing what is known as the “urban heat island” effect. The eastern part is cooler on most occasions due to the Atlantic Ocean and the Long Island Sound and it being less developed. On dry nights with no clouds or wind, the Pine Barrens in eastern Suffolk County can be almost 20 Fahrenheit degrees cooler due to radiational cooling.

Average Long Island Temperatures

  • Average Temperature in January HIGH: 39 Degrees, LOW: 23 Degrees
  • Average Temperature in February HIGH: 41 Degrees, LOW: 24 Degrees
  • Average Temperature in March HIGH: 48 Degrees, LOW: 31 Degrees
  • Average Temperature in April HIGH: 58 Degrees, LOW: 40 Degrees
  • Average Temperature in May HIGH: 69 Degrees, LOW: 49 Degrees
  • Average Temperature in June HIGH: 77 Degrees, LOW: 60 Degrees
  • Average Temperature in July HIGH: 83 Degrees, LOW: 66 Degrees
  • Average Temperature in August HIGH: 82 Degrees, LOW: 64 Degrees
  • Average Temperature in September HIGH: 75 Degrees, LOW: 57 Degrees
  • Average Temperature in October HIGH: 64 Degrees, LOW: 45 Degrees
  • Average Temperature in November HIGH: 54 Degrees, LOW: 36 Degrees
  • Average Temperature in December HIGH: 44 Degrees, LOW: 27 Degrees

Long Island has a climate similar to other coastal areas of the Northeastern United States; it has warm, humid summers and cold winters, but the Atlantic Ocean helps bring afternoon sea breezes that lower the heat in the warmer months and limit the frequency and severity of thunderstorms. However, severe thunderstorms are not uncommon, especially when they approach the island from the mainland areas of the Bronx, Westchester County and Connecticut in the northwest.Some thunderstorms can be extremely severe and tornadoes, though very rare, are possible.

In September 1998, a small tornado hit Lynbrook; in August 1999, an F-2 tornado hit parts of Mattituck, in August 2005, a small tornado hit Glen Cove; one year later in August 2006, a small tornado hit Massapequa in Nassau County, and parts of Amityville, which straddles Nassau and Suffolk counties but is officially located in Suffolk County. On July 18, 2007, an F-1 tornado hit Islip Terrace and on September 27, 2006, a rare waterspout was seen over the Long Island Sound near Port Jefferson. In the wintertime, temperatures are warmer than areas further inland (especially in the night and early morning hours), sometimes causing a snowstorm further inland to fall as rain or mixed precipitation on the island.