New Castle, DE 19720 Frost Dates
New Castle, DE: when does the frost end?
The last spring frost here typically falls around 04/07, about 222 days from today. Fall's first freeze usually shows up around 11/01, roughly 209 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts New Castle in Zone 7b (5 to 10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 9 weeks until New Castle's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around New Castle's last frost
04/07 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/26 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/21 and only about 1 year in 10 sees frost after that.
New Castle against the rest of the dataset
At roughly 209 frost-free days, New Castle places 15,206 of 40,283 ZIP codes in this dataset. Within DE, it ranks 44 of 96.
Learn more
Before leaning on 19720's figures: local microclimates explains what one yard in New Castle can differ from the 19720 normal, while zone vs. frost date explains why Zone 7b and New Castle's frost date answer different questions.