Humidity in New York City, New York Today

New York sits in a humid subtropical climate that shades into continental, which is why its humidity swings so hard between seasons. In summer the Bermuda-Azores High parks off the Atlantic and pumps warm, moisture-laden air straight up the Eastern Seaboard. Dew points climb into the 60s and low 70s°F during heat waves, and because the ocean is right there, that moisture rarely gets a chance to dry out — the result is the heavy, shirt-sticking heat New Yorkers know from mid-July through August.

Winter flips the script. Arctic air sweeping down from Canada is bitterly cold and holds almost no absolute moisture, so the city dries out even though the relative-humidity number can still read high — cold air saturates easily, which is why a 40% winter afternoon feels nothing like a 40% summer one. Spring and fall are the transitional shoulder seasons, when nor'easters can spike moisture for a day or two before a cold front scrubs it back out.

The city's own geography adds a twist you won't see in a regional forecast. Manhattan's dense concrete and asphalt form a powerful urban heat island that keeps overnight temperatures — and therefore overnight humidity — elevated well above the outer boroughs and suburbs. Meanwhile the harbor, the East and Hudson Rivers, and Long Island Sound feed morning fog and dew along the waterfront, so a reading taken in Battery Park can differ noticeably from one in inland Queens.