Frost Dates for 13634 — Dexter, New York

Half of springs at Watertown International Airport, NY see their last 32°F night by May 11; only one in ten is past it by April 29, and one in ten still has one after May 26. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 21 20%, and after May 26 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 29% of the 173 New York stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 16 one year in ten, and holds off past October 13 one year in ten. A hard freeze of 28°F follows 10 days later, around October 11; in spring the one-in-ten date for 28°F is May 14, 12 days before the 32°F one. The freeze-free season lasts 140 days in a typical year, shorter than at 90% of the 173 New York stations; it reaches 160 days one year in ten and falls short of 119 one year in ten. On average 151 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 14 days longer, to about May 25, and return around September 19. Severe cold of 16°F or below comes every winter, usually between November 16 and March 31.

July is the warmest month at Watertown International Airport, NY, averaging 79°F by day and 59°F at night; January is the coldest at 30°F and 10°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 84% of years.

Warmth for growing adds up to 2,207 growing degree days a year (base 50°F), fewer than at 76% of the 173 New York stations. 30% of them (653) have built up by the end of June, and July adds the most, 589. Precipitation totals 37.2 inches a year, most in October (4.2") and least in February (2.2"); May to September bring 43% of it.

The nearest other station, Watertown, NY, 9 miles east of Dexter and 179 feet higher, has a last frost 9 days earlier (May 2), a first frost 12 days later (October 13), a season 23 days longer.

The first measurable snow (0.1 inch or more) in Dexter usually arrives around November 19, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Watertown, NY, 9.4 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 35 days after the last snow.

ZIP 13634 is 2 miles from Watertown International Airport, NY, which stands at 318 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 13605 (Adams). The 2023 USDA Plant Hardiness Zone Map lists ZIP 13634 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.