Frost Dates for 11791 — Syosset, New York

Half of springs at Farmingdale Airport, NY see their last 32°F night by April 6; only one in ten is past it by March 26, and one in ten still has one after April 20. Planting tender crops after April 12 leaves a 30% risk of a frost on them, after April 15 20%, and after April 20 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 63% of the 173 New York stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 6 in half of years, as early as October 25 one year in ten, and holds off past November 21 one year in ten. A hard freeze of 28°F follows 13 days later, around November 19; in spring the one-in-ten date for 28°F is April 6, 14 days before the 32°F one. The freeze-free season lasts 213 days in a typical year, longer than at 92% of the 173 New York stations; it reaches 231 days one year in ten and falls short of 194 one year in ten. On average 88 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 13 days longer, to about April 19, and return around October 26. Severe cold of 16°F or below comes in 99% of winters, usually between January 1 and February 24.

July is the warmest month at Farmingdale Airport, NY, averaging 83°F by day and 68°F at night; January is the coldest at 39°F and 25°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 75% of years.

Warmth for growing adds up to 3,300 growing degree days a year (base 50°F), more than at 93% of the 173 New York stations. 30% of them (984) have built up by the end of June, and July adds the most, 784. Precipitation totals 38.5 inches a year, most in September (3.7") and least in February (2.0"); May to September bring 44% of it.

The nearest other station, Centerport, NY, 8 miles northeast of Syosset, has a last frost 3 days later (April 9), a first frost 4 days later (November 10), a season 2 days longer.

The first measurable snow (0.1 inch or more) in Syosset usually arrives around December 10, and the last of the season around March 16. Those are the middle dates across the winters of 1991–2020 at Centerport, NY, 8.2 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 21 days after the last snow.

ZIP 11791 is 7 miles from Farmingdale Airport, NY, which stands at 81 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 16 other ZIP codes share the station; its figures are presented in full for 11706 (Bay Shore). The 2023 USDA Plant Hardiness Zone Map lists ZIP 11791 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.