Long Island forecast: Mostly sunny for last week of summer; leaf-peeping on the horizon

With only one week left of summer, beachgoers reluctantly yank Boogie boards and lounge chairs out of their cars, and latte loving leaf peepers lay out their sweaters.

Though the last official day of summer is Sept. 21, Sunday was the last day lifeguards were on duty at most Long Island beaches. The South Shore waters were 70 degrees, and surfers basked in their peak season for catching waves. Lifeguards will staff Point Lookout Beach and Lido Beach through Sept. 21, and East Hampton Main Beach through Oct. 12.

Long Islanders can expect "a good deal of sunshine on Monday and Tuesday," with a chance of rain in the second half of the week, said meteorologist Jay Engle with the National Weather Service. Next Friday and Saturday are expected to bring "lots of sunshine" with temperatures in the low 80s and mid-70s, Engle said.

With the Autumn Equinox ringing in fall on Sept. 22 in the Northern Hemisphere, the clock is ticking on beach days, outdoor dining and enjoying an ice cream cone without judgment. For those ready for sweater weather, Long Island’s peak leaf color change is expected to kick off just before Halloween and last through the first two weeks of November.

For now, leaf peepers willing to trek upstate can catch leaves "just changing" in the Adirondacks, Catskills, Capital-Saratoga region and Chautauqua-Allegheny region, according to the state’s I Love NY program. Officials publish fall foliage reports online every Wednesday throughout the season.

By the time Long Islanders are photographing yellow and red hues on the East End, with peak foliage making its way west by mid-November, the rest of New York will be plastered with bare tree branches and a faint memory of warmer days.

According to the State University of New York College of Environmental Science and Forestry, the chemical process that transforms leaves from green to yellow and orange is triggered by changes in temperature and the length of daylight. Long Island sees its color change weeks after the rest of New York because of its warmer weather and location on the coast.

The best places to enjoy peak foliage, according to the state’s program, include the Gold Coast mansions on Long Island's North Shore, the tops of lighthouses on Fire Island and Montauk and vineyards across Long Island’s wine country.

But, like summer, the moment is fleeting: Experts remind leaf enthusiasts that "peak brilliance" lasts just three or four days in any given spot.