Frost Dates for 06489 — Southington, Connecticut

Half of springs at Meriden Markham Municipal Airport, CT see their last 32°F night by April 26; only one in ten is past it by April 11, 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 5 20%, and after May 9 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 86% of the 28 Connecticut stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 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 14 days later, around October 30; in spring the one-in-ten date for 28°F is April 28, 11 days before the 32°F one. The freeze-free season lasts 175 days in a typical year, shorter than at 54% of the 28 Connecticut stations; it reaches 194 days one year in ten and falls short of 156 one year in ten. On average 129 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 7, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 3 and March 9.

July is the warmest month at Meriden Markham Municipal Airport, CT, averaging 84°F by day and 63°F at night; January is the coldest at 37°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 33% of years.

Warmth for growing adds up to 2,927 growing degree days a year (base 50°F), more than at 57% of the 28 Connecticut stations. 31% of them (921) have built up by the end of June, and July adds the most, 721. Precipitation totals 45.0 inches a year, most in October (4.5") and least in February (2.9"); May to September bring 42% of it.

The nearest other station, Burlington, CT, 13 miles north of Southington and 402 feet higher, has a last frost 1 day earlier (April 25), a first frost 2 days later (October 18), a season 3 days shorter.

The first measurable snow (0.1 inch or more) in Southington usually arrives around December 9, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Shuttle Meadow Rsvr, CT, 3.6 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 36 days after the last snow.

ZIP 06489 is 7 miles from Meriden Markham Municipal Airport, CT, which stands at 103 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 21 other ZIP codes share the station; its figures are presented in full for 06457 (Middletown). The 2023 USDA Plant Hardiness Zone Map lists ZIP 06489 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.