Frost Dates for 06241 — Dayville, Connecticut

Half of springs at N Foster 1 E, RI see their last 32°F night by April 25; only one in ten is past it by April 13, and one in ten still has one after May 9. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 4 20%, and after May 9 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 54% of the 28 Connecticut stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 19 in half of years, as early as October 4 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 11 days later, around October 30; in spring the one-in-ten date for 28°F is April 26, 13 days before the 32°F one. The freeze-free season lasts 176 days in a typical year, longer than at 50% of the 28 Connecticut stations; it reaches 195 days one year in ten and falls short of 156 one year in ten. On average 133 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 12 days longer, to about May 7, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 5 and March 15.

July is the warmest month at N Foster 1 E, RI, averaging 80°F by day and 61°F at night; January is the coldest at 35°F and 19°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 31% of years.

Warmth for growing adds up to 2,556 growing degree days a year (base 50°F), fewer than at 79% of the 28 Connecticut stations. 31% of them (786) have built up by the end of June, and July adds the most, 646. Precipitation totals 53.8 inches a year, most in March (5.2") and least in July (3.6"); May to September bring 39% of it.

The nearest other station, W Thompson Lake, CT, 7 miles north of Dayville and 270 feet lower, has a last frost 6 days later (May 1), a first frost 10 days earlier (October 9), a season 15 days shorter.

The first measurable snow (0.1 inch or more) in Dayville usually arrives around November 18, and the last of the season around April 1. Those are the middle dates across the winters of 1991–2020 at N Foster 1 E, RI, 6.4 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 24 days after the last snow.

ZIP 06241 is 6 miles from N Foster 1 E, RI, which stands at 630 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 06239 (Danielson). The 2023 USDA Plant Hardiness Zone Map lists ZIP 06241 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.