Hillsborough, NC 27515 Frost Dates
27515, near Hillsborough, NC: the frost window
Typically, the last spring freeze lands around 03/31, roughly 215 days out. Fall's first freeze usually shows up around 11/04, roughly 217 days after the last spring frost.
Zone 8a (10 to 15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Hillsborough, not a forecast for this year.
Stretching the season past the first frost
Hillsborough's growing season runs out in roughly 10 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 03/31 isn't a guarantee
03/31 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/19 and only about 1 year in 10 sees frost after that.
Hillsborough against the rest of the dataset
Hillsborough's growing season runs about 217 days, ranking 13,450 of 40,283 US ZIP codes measured here, longest to shortest. Within NC, it ranks 668 of 1,078.
Learn more
Two guides worth reading on 27515: zone vs. frost date, on why Zone 8a and Hillsborough's frost date answer different questions, and the frost range, on how to read the range around Hillsborough's dates instead of trusting one.