New York City  has plenty to offer year-round, but the best times to visit are spring, early summer, and fall, when temperatures are moderate and conducive to exploring on foot. Autumns are often especially wonderful, with deep cobalt blue skies and the excitement of a new season in the air. Winter in New York can be bitterly cold (in the 20s, with bone-chilling winds), mid-summers stiflingly hot (in the 90s, with high humidity).
The climate upstate varies considerably from region to region. Long Island  is lovely in the spring and fall, but if you’re a beach lover, you’ll probably want to come in summer, when the beaches are in full swing; bear in mind, however, that between Memorial Day and Labor Day, traffic on the island is horrendous.
The Hudson Valley  is a terrific destination at any time of year, though some attractions close down in winter and mid-summers are often hot and humid. The Catskills  and central New York are best visited in the summer, when they provide a welcome retreat from the heat, and in the fall, when fall foliage is a major draw.
Unless you’re a skier, summer and early fall are really the only times to visit the Adirondacks  and Thousand Islands . Winters are frigid, and many attractions are only open in July and August. Fall foliage is usually magnificent, especially in the Adirondacks.
The Finger Lakes  and western New York are best visited in the summer and fall as well. In the winter, temperatures near Lake Ontario (including Rochester) and Lake Erie (including Buffalo) drop precipitously.