Castroville, TX 78066 Frost Dates
78066, near Castroville, TX: the frost window
Typically, the last spring freeze lands around 02/18, roughly 174 days out. Fall's first freeze usually shows up around 12/09, roughly 296 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Castroville in Zone 9a (20 to 25°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
Castroville's growing season runs out in roughly 15 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
02/18 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 03/16 and only about 1 year in 10 sees frost after that.
Castroville against the rest of the dataset
About 296 days separate Castroville's last and first frost, putting it 4,243 of 40,283 ZIP codes nationally. Within TX, it ranks 512 of 2,558.
Learn more
Two guides worth reading on 78066: zone vs. frost date, on why Zone 9a and Castroville's frost date answer different questions, and the frost range, on how to read the range around Castroville's dates instead of trusting one.