Frost Dates for 37861 — Rutledge, Tennessee

Half of springs at Morristown WFO, TN see their last 32°F night by March 31; only one in ten is past it by March 14, and one in ten still has one after April 18. Planting tender crops after April 6 leaves a 30% risk of a frost on them, after April 12 20%, and after April 18 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 67% of the 144 Tennessee stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 4 in half of years, as early as October 22 one year in ten, and holds off past November 18 one year in ten. A hard freeze of 28°F follows 10 days later, around November 14; in spring the one-in-ten date for 28°F is April 5, 13 days before the 32°F one. The freeze-free season lasts 217 days in a typical year, longer than at 85% of the 144 Tennessee stations; it reaches 242 days one year in ten and falls short of 195 one year in ten. On average 64 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 April 14, and return around October 26. Severe cold of 16°F or below comes in 97% of winters, usually between December 31 and February 6.

July is the warmest month at Morristown WFO, TN, averaging 86°F by day and 68°F at night; January is the coldest at 46°F and 29°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 49% of years.

Warmth for growing adds up to 4,318 growing degree days a year (base 50°F), fewer than at 65% of the 144 Tennessee stations. 38% of them (1,653) have built up by the end of June, and July adds the most, 823. Precipitation totals 47.5 inches a year, most in July (5.0") and least in October (2.7"); May to September bring 40% of it.

The nearest other station, Jefferson City, TN, 9 miles south of Rutledge and 212 feet lower, has a last frost 24 days later (April 24), a first frost 18 days earlier (October 17), a season 42 days shorter.

The first measurable snow (0.1 inch or more) in Rutledge usually arrives around December 12, and the last of the season around March 9. Those are the middle dates across the winters of 1991–2020 at Morristown WFO, TN, 8.1 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 22 days after the last snow.

ZIP 37861 is 8 miles from Morristown WFO, TN, which stands at 1,320 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 37877 (Talbott). The 2023 USDA Plant Hardiness Zone Map lists ZIP 37861 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.