When to plant in Alton, TX
USDA Zone 10aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Alton, Texas — all computed from Alton's nearest NOAA weather station.
A generous ~339-day season lets Alton gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. Zone 10a is warm enough that Alton can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average first fall frost in Alton is now 6 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
LA JOYA · 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 Alton’s own odds, recorded at LA JOYA.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 11 | Feb 11 | Jan 9 | Nov 18 | Dec 7 | Jan 7 |
| 32°F | Feb 27 | Jan 23 | Dec 22 | Dec 2 | Dec 28 | Feb 1 |
| 28°F | Feb 6 | Jan 7 | Dec 17 | Dec 13 | Jan 1 | Feb 1 |
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 Alton, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 13 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.
Alton planting FAQ
When is the last spring frost in Alton, TX?
Plan for the last spring frost in Alton around January 23 (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 Alton, TX?
In Alton, the first 32°F freeze of fall lands around December 28 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Alton in?
Alton is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Alton?
There are roughly 339 frost-free days in Alton (a long growing season), running from the average last frost around January 23 to the first fall frost near December 28.
When should I plant tomatoes in Alton?
In Alton, start tomato seeds indoors around November 28–December 12, then transplant seedlings outdoors around January 30 once the danger of frost has passed.
Never miss a window in Alton
An email when it’s time to start seeds, transplant, and sow — timed to Alton’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at LA JOYA, 4 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 Alton, TX — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00414911. Retrieved from https://blissgarden.com/texas/alton.