Frost Dates for 37342 — Hillsboro, Tennessee

Half of springs at Manchester #2, TN see their last 32°F night by April 13; only one in ten is past it by March 27, and one in ten still has one after April 30. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 25 20%, and after April 30 10%. The 17 days between the even-odds date and the one-in-ten date is narrower than at 34% of the 144 Tennessee stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 24 in half of years, as early as October 11 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 8 days later, around November 1; in spring the one-in-ten date for 28°F is April 18, 12 days before the 32°F one. The freeze-free season lasts 192 days in a typical year, shorter than at 77% of the 144 Tennessee stations; it reaches 213 days one year in ten and falls short of 172 one year in ten. On average 94 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 26, and return around October 15. Severe cold of 16°F or below comes in 99% of winters, usually between December 11 and February 17.

July is the warmest month at Manchester #2, TN, averaging 86°F by day and 65°F at night; January is the coldest at 47°F and 26°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 81% of years.

Warmth for growing adds up to 3,959 growing degree days a year (base 50°F), fewer than at 83% of the 144 Tennessee stations. 37% of them (1,477) have built up by the end of June, and July adds the most, 801. Precipitation totals 59.5 inches a year, most in December (6.6") and least in October (3.5"); May to September bring 37% of it.

The nearest other station, Sewanee, TN, 13 miles south of Hillsboro and 858 feet higher, has a last frost 11 days earlier (April 2), a first frost 11 days later (November 4), a season 24 days longer.

The first measurable snow (0.1 inch or more) in Hillsboro usually arrives around January 13, and the last of the season around February 12. Those are the middle dates across the winters of 1991–2020 at Tullahoma, TN, 14.2 miles away: half of years saw snow earlier, half later. Snow fell in 89% of those winters. The last 32°F night of spring typically comes 60 days after the last snow.

ZIP 37342 is 11 miles from Manchester #2, TN, which stands at 1,070 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 37355 (Manchester). The 2023 USDA Plant Hardiness Zone Map lists ZIP 37342 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.