When to plant in San Juan, TX
USDA Zone 10aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for San Juan, Texas — all computed from San Juan's nearest NOAA weather station.
With only about -8 frost-free days, San Juan has a short season — start heat-lovers indoors early, favor quick-maturing varieties, and use row cover to stretch both ends. Zone 10a is warm enough that San Juan can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
MCALLEN · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are San Juan’s own odds, recorded at MCALLEN.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 1 | Jan 27 | Dec 20 | Nov 27 | Dec 19 | Jan 26 |
| 32°F | Feb 12 | Jan 9 | Dec 14 | Dec 8 | Jan 1 | Feb 4 |
| 28°F | Feb 9 | Jan 4 | Dec 15 | Dec 14 | Jan 2 | Feb 6 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.
Full-year planting calendar
Each bar is the exact window to take a planting action in San Juan, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 12 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
San Juan planting FAQ
When is the last spring frost in San Juan, TX?
Plan for the last spring frost in San Juan around January 9 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in San Juan, TX?
In San Juan, the first 32°F freeze of fall lands around January 1 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is San Juan in?
San Juan is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in San Juan?
There are roughly -8 frost-free days in San Juan (a short growing season), running from the average last frost around January 9 to the first fall frost near January 1.
When should I plant tomatoes in San Juan?
In San Juan, start tomato seeds indoors around November 14–November 28, then transplant seedlings outdoors around January 16 once the danger of frost has passed.
Never miss a window in San Juan
An email when it’s time to start seeds, transplant, and sow — timed to San Juan’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at MCALLEN, 10 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in San Juan, TX — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00415701. Retrieved from https://blissgarden.com/texas/san-juan.