San Juan, TX 78577 Frost Dates
San Juan, TX: when does the frost end?
The last spring frost here typically falls around 01/09, about 134 days from today. Fall's first freeze usually shows up around 01/03, roughly 365 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts San Juan in Zone 10a (30 to 35°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 18 weeks until San Juan's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
01/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/13 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/17 and only about 1 year in 10 sees frost after that.
San Juan against the rest of the dataset
San Juan's growing season runs about 365 days, ranking 993 of 40,283 US ZIP codes measured here, longest to shortest. Within TX, it ranks 23 of 2,558.
Learn more
Before leaning on 78577's figures: zone vs. frost date explains why Zone 10a and San Juan's frost date answer different questions, while the frost range explains how to read the range around San Juan's dates instead of trusting one.