When to plant in San Marcos, TX
USDA Zone 9aEverything below — frost dates, hardiness zone, and what to plant when in San Marcos, Texas — is derived from the closest NOAA station with complete climate normals.
San Marcos enjoys a long ~274-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. Zone 9a is warm enough that San Marcos can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
SAN MARCOS · 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 Marcos’s own odds, recorded at SAN MARCOS.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 5 | Mar 14 | Feb 23 | Nov 1 | Nov 16 | Dec 4 |
| 32°F | Mar 21 | Feb 28 | Feb 1 | Nov 8 | Nov 29 | Dec 21 |
| 28°F | Mar 8 | Feb 13 | Jan 9 | Nov 19 | Dec 15 | Jan 13 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in San Marcos, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 21 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 Marcos planting FAQ
When is the last spring frost in San Marcos, TX?
On average, the last spring frost in San Marcos is around February 28 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in San Marcos, TX?
Expect San Marcos's first fall frost near November 29 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is San Marcos in?
San Marcos is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in San Marcos?
There are roughly 274 frost-free days in San Marcos (a long growing season), running from the average last frost around February 28 to the first fall frost near November 29.
When should I plant tomatoes in San Marcos?
In San Marcos, start tomato seeds indoors around January 3–January 17, then transplant seedlings outdoors around March 7 once the danger of frost has passed.
Never miss a window in San Marcos
An email when it’s time to start seeds, transplant, and sow — timed to San Marcos’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Kyle · 14 km
- Buda · 24 km
- Lockhart · 25 km
- New Braunfels · 26 km
- Canyon Lake · 31 km
- Seguin · 32 km
- Cibolo · 44 km
- Schertz · 46 km
Frost dates recorded at SAN MARCOS, 2 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 Marcos, TX — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00417983. Retrieved from https://blissgarden.com/texas/san-marcos.