Weather in Long Island: Climate, Seasons, and Average Monthly Temperature

weather and climate on Long Island

 TripSavvy / Ellen Lindner

Bordered by the East River, Long Island Sound, and the Atlantic Ocean, Long Island generally follows a four-season weather pattern. Summer is hot, sunny, and somewhat humid, whereas winter is cold, often with snow.

The hottest month of the year is July when the average high is around 83 degrees F (28 degrees C). The coldest month is usually January, when temperatures can drop to an average low of 23 degrees F (-5 degrees C). Nassau County tends to be a bit warmer than Suffolk County since it is closer to the mainland of New York City and more densely populated.

The region gets rain any time of year; however, March, June, and December receive the most inches of rain on average. Snow is possible between November and April, but it most commonly occurs in January and February (these two months also have the highest average inches of snowfall). If you are planning to travel here and snow is in the forecast, check with your transportation provider and hotel to see if it may affect your trip.

Long Island is a year-round destination, but most people visit during the summer—especially beach-goers. The water will generally be warm enough to swim in June to September (unless you’re into polar bear plunges!). July and August are the most popular months to visit, while spring and fall provide a quieter, but no less fun, experience. Although winter is the least popular time for tourists, some places have winter-specific activities. On the flip-side, certain attractions, hotels, and restaurants may be closed in winter (particularly in beach towns), so check opening dates carefully.

No matter which season you choose to visit, as long as you’re prepared for the appropriate weather, you’re sure to have fun. If you’re planning a beach trip and rain is in the forecast, be sure and check out what kind of indoor activities Long Island has to offer.

Fast Climate Facts

  • Hottest Month: July, 85 degrees F
  • Coldest Month: January, 40 degrees F
  • Wettest Months: March and July, 4.4 inches

Spring in Long Island

Early spring still feels pretty chilly thanks to the humidity on Long Island—but by late spring things begin to warm up. Highs range from 48 to 70 degrees F (9 to 21 degrees C), and lows are between 31 and 51 degrees F (-.5 and 10.5 degrees C) on average. Rain is somewhat common, with seven to eight days of significant precipitation per month.

What to Pack: Layers are key here because, while midday might feel hot some days, mornings and evenings will still be chilly. Pack a selection of T-shirts, sweaters, a scarf, and a jacket. Don't forget your rain gear. It’s probably still too cold for shorts and swimsuits, so leave those at home.

Average Temperatures by Month

March: High: 50 degrees F; Low: 34 degrees F

April: High: 60 degrees F; Low: 42 degrees F

May: High: 70 degrees F; Low: 51 degrees F

Summer in Long Island

Summer in Long Island is wonderful, but be prepared for some humidity and a possible rainy day or two. In general, the sun will be shining and beaches will be packed!

What to Pack: Pack short and long-sleeved T-shirts, tank tops, shorts, light pants and jeans, light dresses, swimsuits, sunglasses, and of course, sunscreen. A sweater or sweatshirt is a good idea for cooler evenings, especially in June. Check the forecast for rain and bring a light rain jacket or umbrella if necessary.

Average Temperatures by Month

June: High: 80 degrees F; Low: 61 degrees F

July: High: 85 degrees F; Low: 66 degrees F

August: 83 degrees F; Low: 65 degrees F

Fall in Long Island

Fall in Long Island can be hot, wet, cool, or some combination of all three. September is usually still warm in Long Island, while it can be quite chilly by November. Humidity decreases to a comfortable level and a cooling breeze is often present. Rain is possible.

What to Pack: Packing for September will be quite different from November. If it's the former, you’ll want layers like T-shirts, sweaters, and jackets, along with jeans and shorts for warmer days. The water is often still warm this month, so bring your swimsuit. October and November are cooler; pack jeans and sweaters, as well as a vest (or heavy jacket) and scarf. Sunglasses and sunscreen are still necessary, and always toss in rain gear.

Average Temperatures by Month

September: High: 76 degrees F; Low: 58 degrees F

October: High: 65 degrees F; Low: 48 degrees F

November: High: 55 degrees F; Low: 40 degrees F

Winter in Long Island

Winters in Long Island are cold, and sometimes downright frigid. On average, it rains or snows about seven to nine times per month. The sun might shine some days, but the temperatures will remain frosty.

What to Pack: You’ll definitely need a warm coat, hat, gloves, and scarf if you plan to spend any time outdoors. If snow is predicted or has already fallen, bring waterproof and insulated boots. Thick sweaters and sweatshirts, jeans, wool pants, warm leggings, and fleece will keep you cozy.

Average Temperatures by Month

December: High: 45 degrees F; Low: 31 degrees F

January: High: 40 degrees F; Low: 26 degrees F

February: High: 42 degrees F; Low: 28 degrees F

Average Monthly Temperature, Rainfall, and Daylight Hours
Month Avg. Temp. Rainfall Daylight Hours
January 40 F 3.6 inches 10 hours
February 42 F 3.2 inches 11 hours
March 50 F 4.4 inches 12 hours
April 60 F 4.2 inches 13 hours
May 70 F 3.9 inches 14 hours
June 80 F 3.9 inches 15 hours
July 85 F 4.4 inches 15 hours
August 83 F 3.7 inches 14 hours
September 76 F 3.9 inches 12 hours
October 65 F 4.1 inches 11 hours
November 55 F 3.7 inches 10 hours
December 45 F 3.8 inches 9 hours
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