Frost Dates for 27514 — Chapel Hill, North Carolina

Half of springs at Chapel Hill Williams Airport, NC see their last 32°F night by March 29; only one in ten is past it by March 11, and one in ten still has one after April 12. Planting tender crops after April 4 leaves a 30% risk of a frost on them, after April 7 20%, and after April 12 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 79% of the 173 North Carolina stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 5 in half of years, as early as October 23 one year in ten, and holds off past November 21 one year in ten. A hard freeze of 28°F follows 12 days later, around November 17; in spring the one-in-ten date for 28°F is April 2, 10 days before the 32°F one. The freeze-free season lasts 222 days in a typical year, longer than at 61% of the 173 North Carolina stations; it reaches 246 days one year in ten and falls short of 202 one year in ten. On average 68 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 11, and return around October 28. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 71%.

July is the warmest month at Chapel Hill Williams Airport, NC, averaging 90°F by day and 69°F at night; January is the coldest at 51°F and 32°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 40% of years.

Warmth for growing adds up to 4,839 growing degree days a year (base 50°F), more than at 58% of the 173 North Carolina stations. 39% of them (1,880) have built up by the end of June, and July adds the most, 913. Precipitation totals 43.7 inches a year, most in June (4.4") and least in February (2.8"); May to September bring 46% of it.

The nearest other station, Chapel Hill 2 W, NC, 3 miles west of Chapel Hill, has a last frost 2 days later (March 31), a first frost 2 days earlier (November 3), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Chapel Hill usually arrives around January 10, and the last of the season around February 20. Those are the middle dates across the winters of 1991–2020 at Raleigh Durham International Airport, NC, 13.9 miles away: half of years saw snow earlier, half later. Snow fell in 87% of those winters. The last 32°F night of spring typically comes 37 days after the last snow.

ZIP 27514 is 2 miles from Chapel Hill Williams Airport, NC, which stands at 512 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 27514 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°C) over 1991–2020; a zone describes winter lows, not frost dates.