Frost Dates for 19958 — Lewes, Delaware

Half of springs at Lewes, DE see their last 32°F night by March 29; only one in ten is past it by March 13, and one in ten still has one after April 9. Planting tender crops after April 2 leaves a 30% risk of a frost on them, after April 5 20%, and after April 9 10%. The 11 days between the even-odds date and the one-in-ten date is narrower than at 90% of the 10 Delaware stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 14 in half of years, as early as November 1 one year in ten, and holds off past December 1 one year in ten. A hard freeze of 28°F follows 14 days later, around November 28; in spring the one-in-ten date for 28°F is March 30, 10 days before the 32°F one. The freeze-free season lasts 231 days in a typical year, the longest of the 10 Delaware stations; it reaches 253 days one year in ten and falls short of 213 one year in ten. On average 59 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 11 days longer, to about April 9, and return around November 3. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 86%.

July is the warmest month at Lewes, DE, averaging 88°F by day and 71°F at night; January is the coldest at 46°F and 30°F. A freezing night is all but certain in every month from December to March (a 90% chance or more). From May to October the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 37% of years.

Warmth for growing adds up to 4,422 growing degree days a year (base 50°F), the most of the 10 Delaware stations. 35% of them (1,534) have built up by the end of June, and July adds the most, 904. Precipitation totals 47.5 inches a year, most in July (5.0") and least in February (3.2"); May to September bring 44% of it.

The nearest other station, Georgetown Sussex Co Airport, DE, 11 miles west of Lewes, has a last frost 6 days later (April 4), a first frost 8 days earlier (November 6), a season 14 days shorter.

The first measurable snow (0.1 inch or more) in Lewes usually arrives around January 22, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Lewes, DE, 2.6 miles away: half of years saw snow earlier, half later. Snow fell in 74% of those winters. The last 32°F night of spring typically comes 31 days after the last snow.

ZIP 19958 is 3 miles from Lewes, DE, which stands at 10 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 19958 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.