Frost Dates for 06795 — Watertown, Connecticut

Half of springs at Burlington, CT see their last 32°F night by April 25; only one in ten is past it by April 12, and one in ten still has one after May 10. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 5 20%, and after May 10 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 50% of the 28 Connecticut stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as October 4 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 12 days later, around October 30; in spring the one-in-ten date for 28°F is April 29, 11 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, shorter than at 61% of the 28 Connecticut stations; it reaches 192 days one year in ten and falls short of 151 one year in ten. On average 142 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 11 days longer, to about May 6, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 6 and March 14.

July is the warmest month at Burlington, CT, averaging 84°F by day and 62°F at night; January is the coldest at 36°F and 17°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 32% of years.

Warmth for growing adds up to 2,830 growing degree days a year (base 50°F), more than at 54% of the 28 Connecticut stations. 31% of them (888) have built up by the end of June, and July adds the most, 710. Precipitation totals 53.5 inches a year, most in October (5.7") and least in February (3.4"); May to September bring 44% of it.

The nearest other station, Meriden Markham Municipal Airport, CT, 17 miles southeast of Watertown and 402 feet lower, has a last frost 1 day later (April 26), a first frost 2 days earlier (October 16), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Watertown usually arrives around November 30, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Woodbury, CT, 6.8 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 31 days after the last snow.

ZIP 06795 is 16 miles from Burlington, CT, which stands at 505 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 13 other ZIP codes share the station; its figures are presented in full for 06010 (Bristol). The 2023 USDA Plant Hardiness Zone Map lists ZIP 06795 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.