Frost Dates for 29678 — Seneca, South Carolina

Half of springs at Clemson Oconee Co Airport, SC see their last 32°F night by March 21; only one in ten is past it by March 1, and one in ten still has one after April 7. Planting tender crops after March 28 leaves a 30% risk of a frost on them, after April 1 20%, and after April 7 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 57% of the 105 South Carolina stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 11 in half of years, as early as October 28 one year in ten, and holds off past December 1 one year in ten. A hard freeze of 28°F follows 16 days later, around November 27; in spring the one-in-ten date for 28°F is March 24, 14 days before the 32°F one. The freeze-free season lasts 236 days in a typical year, longer than at 62% of the 105 South Carolina stations; it reaches 263 days one year in ten and falls short of 212 one year in ten. On average 38 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 3, and return around November 1. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 59%.

July is the warmest month at Clemson Oconee Co Airport, SC, averaging 89°F by day and 70°F at night; January is the coldest at 52°F and 34°F. A freezing night is all but certain in every month from December to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 88% of years and April still brings one in 22% of years.

Warmth for growing adds up to 4,946 growing degree days a year (base 50°F), fewer than at 80% of the 105 South Carolina stations. 39% of them (1,931) have built up by the end of June, and July adds the most, 908. Precipitation totals 49.1 inches a year, most in August (4.9") and least in May (3.5"); May to September bring 41% of it.

The nearest other station, Clemson Univ, SC, 7 miles east of Seneca, has a last frost 11 days later (April 1), a first frost 8 days earlier (November 3), a season 19 days shorter.

The first measurable snow (0.1 inch or more) in Seneca usually arrives around January 20, and the last of the season around January 24. Those are the middle dates across the winters of 1991–2020 at Clemson Univ, SC, 6.9 miles away: half of years saw snow earlier, half later. Snow fell in 79% of those winters. The last 32°F night of spring typically comes 56 days after the last snow.

ZIP 29678 is 4 miles from Clemson Oconee Co Airport, SC, which stands at 891 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 29678 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.