When to plant in El Mirage, AZ
USDA Zone 9bEl Mirage, Arizona frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
With about 329 frost-free days, El Mirage supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. In zone 9b, frost is a minor factor for El Mirage — most perennials thrive, and annual vegetables can go out early and stay late.
The average last spring frost in El Mirage is now 7 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
YOUNGTOWN · 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 El Mirage’s own odds, recorded at YOUNGTOWN.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 4 | Feb 14 | Jan 21 | Nov 17 | Dec 2 | Dec 18 |
| 32°F | Feb 18 | Jan 20 | Dec 23 | Nov 28 | Dec 15 | Jan 7 |
| 28°F | Feb 1 | Jan 3 | Dec 13 | Dec 10 | Dec 29 | Jan 22 |
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 El Mirage, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 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.
El Mirage planting FAQ
When is the last spring frost in El Mirage, AZ?
El Mirage's average last spring frost falls near January 20 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in El Mirage, AZ?
The first fall frost in El Mirage typically arrives around December 15 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is El Mirage in?
El Mirage is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in El Mirage?
El Mirage has about 329 frost-free days — a long growing season — between the average last spring frost (January 20) and first fall frost (December 15).
When should I plant tomatoes in El Mirage?
For El Mirage, sow tomatoes indoors about November 25–December 9 and move the seedlings out around January 27, after the last spring frost.
Never miss a window in El Mirage
An email when it’s time to start seeds, transplant, and sow — timed to El Mirage’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at YOUNGTOWN, 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 El Mirage, AZ — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00029634. Retrieved from https://blissgarden.com/arizona/el-mirage.