When to plant in Casa Grande, AZ
USDA Zone 9aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Casa Grande, Arizona — all computed from Casa Grande's nearest NOAA weather station.
A generous ~304-day season lets Casa Grande gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. Zone 9a is warm enough that Casa Grande can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average last spring frost in Casa Grande is now 10 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
CASA GRANDE · 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 Casa Grande’s own odds, recorded at CASA GRANDE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 16 | Feb 26 | Jan 31 | Nov 7 | Nov 24 | Dec 11 |
| 32°F | Feb 28 | Feb 5 | Jan 5 | Nov 18 | Dec 6 | Dec 29 |
| 28°F | Feb 15 | Jan 14 | Dec 16 | Nov 29 | Dec 22 | Jan 24 |
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 Casa Grande, 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.
Casa Grande planting FAQ
When is the last spring frost in Casa Grande, AZ?
Casa Grande's average last spring frost falls near February 5 — 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 Casa Grande, AZ?
In Casa Grande, the first 32°F freeze of fall lands around December 6 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Casa Grande in?
Casa Grande is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Casa Grande?
There are roughly 304 frost-free days in Casa Grande (a long growing season), running from the average last frost around February 5 to the first fall frost near December 6.
When should I plant tomatoes in Casa Grande?
In Casa Grande, start tomato seeds indoors around December 11–December 25, then transplant seedlings outdoors around February 12 once the danger of frost has passed.
Never miss a window in Casa Grande
An email when it’s time to start seeds, transplant, and sow — timed to Casa Grande’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Coolidge · 23 km
- Eloy · 24 km
- Maricopa · 27 km
- San Tan Valley · 36 km
- Sun Lakes · 36 km
- Florence · 37 km
- Queen Creek · 40 km
- Chandler · 43 km
Frost dates recorded at CASA GRANDE, 5 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 Casa Grande, AZ — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00021306. Retrieved from https://blissgarden.com/arizona/casa-grande.