Ajo, AZ frost dates
Frost is light and occasional here — typically a few cold nights around midwinter (about 2 a year). Cover tender plants when frost is forecast.
How Ajo compares
- In a typical year, frost nights in Ajo fall between December 21 and January 10. In 1 year in 10 the first frost comes as early as November 25, or the last frost as late as February 15.
- Compared with Casa Grande, AZ, 112 km away, the last frost here is 26 days earlier than there.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 11 |
| 50% (median) | January 10 |
| 10% (safe for tender plants) | February 15 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 25 |
| 50% (median) | December 21 |
| 90% (late) | January 24 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Gardening where frost is rare
Ajo, AZ only freezes on a few winter nights, so the usual "plant after the last frost" rule doesn't apply. Heat and rainfall decide the seasons instead:
- Cool-season crops (lettuce, broccoli, peas, carrots) grow best from fall through late winter.
- Warm-season crops (tomatoes, peppers, beans, squash) do best planted in late winter to spring, and again in late summer for a fall crop — midsummer heat can stop tomatoes setting fruit.
- Heat lovers (okra, sweet potatoes, melons) can be planted through spring and early summer.
About these dates
Based on 1991–2020 NOAA climate normals for the Ajo, AZ weather station, 25 km away (elevation 1,752 ft (534 m)).
Frost dates near Ajo
- Lukeville Feb 4 · Dec 15
- Sells Apr 26 · Nov 4
- Gila Bend Jan 23 · Dec 11
- Topawa Apr 26 · Nov 4
- Stanfield Feb 5 · Dec 6
- Dateland Jan 25 · Dec 13
- Maricopa Feb 23 · Nov 24
- Arizona City Feb 28 · Nov 21
- Casa Grande Feb 5 · Dec 6
- Eloy Feb 24 · Nov 28
Frequently asked questions
When is the last frost in Ajo, AZ?
The median last spring frost in Ajo, AZ is January 10. There is still about a 10% chance of frost after February 15, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ajo, AZ?
The median first fall frost is December 21, with about a 10% chance of frost before November 25.
How long is the growing season in Ajo, AZ?
About 345 days between the median last spring frost and first fall frost.
What planting zone is Ajo, AZ?
Ajo, AZ is in USDA hardiness zone 9b.