Frost Dates for 37640 — Butler, Tennessee

Half of springs at Flat Springs 1E, NC see their last 32°F night by April 18; only one in ten is past it by April 3, and one in ten still has one after May 7. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 30 20%, and after May 7 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 84% 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 6 one year in ten. A hard freeze of 28°F follows 9 days later, around November 2; in spring the one-in-ten date for 28°F is April 21, 16 days before the 32°F one. The freeze-free season lasts 188 days in a typical year, shorter than at 85% of the 144 Tennessee stations; it reaches 209 days one year in ten and falls short of 166 one year in ten. On average 95 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 2, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 10 and March 3.

July is the warmest month at Flat Springs 1E, NC, averaging 79°F by day and 61°F at night; January is the coldest at 42°F and 24°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 20% of years.

Warmth for growing adds up to 2,884 growing degree days a year (base 50°F), fewer than at 99% of the 144 Tennessee stations. 36% of them (1,036) have built up by the end of June, and July adds the most, 612. Precipitation totals 49.1 inches a year, most in June (5.2") and least in September (3.0"); May to September bring 45% of it.

The nearest other station, Beech Mountain, NC, 12 miles southeast of Butler and 1,723 feet higher, has a last frost 18 days later (May 6), a first frost 10 days earlier (October 14), a season 29 days shorter.

The first measurable snow (0.1 inch or more) in Butler usually arrives around November 23, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at Banner Elk, NC, 13.3 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 18 days after the last snow.

ZIP 37640 is 7 miles from Flat Springs 1E, NC, which stands at 3,330 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 28692 (Vilas). The 2023 USDA Plant Hardiness Zone Map lists ZIP 37640 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.