When to plant in San Luis, AZ
USDA Zone 10aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for San Luis, Arizona — all computed from San Luis's nearest NOAA weather station.
With about 354 frost-free days, San Luis supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. San Luis's nearest full-normals station sits about 28 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. In zone 10a, frost is a minor factor for San Luis — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
YUMA QUARTERMASTER DEPOT · 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 Luis’s own odds, recorded at YUMA QUARTERMASTER DEPOT.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Feb 28 | Jan 28 | Dec 25 | Nov 29 | Dec 16 | Jan 5 |
| 32°F | Feb 19 | Jan 8 | Dec 17 | Dec 11 | Dec 28 | Feb 7 |
| 28°F | Feb 16 | Jan 1 | Dec 19 | Dec 16 | Dec 31 | Feb 10 |
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 Luis, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
2 within 50 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 Luis planting FAQ
When is the last spring frost in San Luis, AZ?
On average, the last spring frost in San Luis is around January 8 (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 Luis, AZ?
The first fall frost in San Luis typically arrives around December 28 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is San Luis in?
San Luis 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 Luis?
San Luis has about 354 frost-free days — a long growing season — between the average last spring frost (January 8) and first fall frost (December 28).
When should I plant tomatoes in San Luis?
For San Luis, sow tomatoes indoors about November 13–November 27 and move the seedlings out around January 15, after the last spring frost.
Never miss a window in San Luis
An email when it’s time to start seeds, transplant, and sow — timed to San Luis’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at YUMA QUARTERMASTER DEPOT, 28 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 Luis, AZ — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00029656. Retrieved from https://blissgarden.com/arizona/san-luis.