Castle Hills, TX 78216 Frost Dates
78216, near Castle Hills, TX: the frost window
The last spring frost here typically falls around 02/26, about 182 days from today. Fall's first freeze usually shows up around 11/28, roughly 277 days after the last spring frost.
Zone 9a (20 to 25°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 Castle Hills, not a forecast for this year.
Stretching the season past the first frost
Castle Hills's growing season runs out in roughly 13 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 02/26 isn't a guarantee
02/26 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 03/17 and only about 1 year in 10 sees frost after that.
Castle Hills against the rest of the dataset
At roughly 277 frost-free days, Castle Hills places 5,014 of 40,283 ZIP codes in this dataset. Within TX, it ranks 812 of 2,558.
Learn more
Two guides worth reading on 78216: local microclimates, on what one yard in Castle Hills can differ from the 78216 normal, and zone vs. frost date, on why Zone 9a and Castle Hills's frost date answer different questions.