Frost dates · USDA zone 9b
Frost dates for Phoenix, AZ
Phoenix, AZ sees its last 32 °F night of spring around January 8 and its first of fall around December 25 — a 354-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Dec 16 (prior winter) | Jan 23 (next year) |
| Median — 1 year in 2 | Jan 8 | Dec 25 |
| 1 year in 10 | Feb 12 | Dec 5 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 354 days median, at least 320 in 9 years of 10, no freeze at all in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Jan 8 and first of Jan 7 (next year).
Phoenix planting calendar, 2027
Every row runs from the median last frost (Jan 8) and median first frost (Dec 25) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Oct 16 | Dec 11 | Mar 31 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Jan 8 | Feb 7 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Dec 25 | Dec 25 | Feb 8 | 45 from sow |
| Genovese BasilGenovese | Dec 11 | Jan 22 | Mar 23 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Nov 13 | Jan 15 | Mar 31 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Oct 30 | Jan 22 | Apr 27 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Nov 13 | Jan 15 | Mar 31 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Nov 13 | Jan 15 | Apr 5 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Nov 13 | Jan 15 | Apr 5 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Dec 25 | Dec 25 | Mar 5 | 70 from sow |
| TomatilloToma Verde | Nov 27 | Jan 15 | Mar 26 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Nov 27 | Jan 15 | Mar 31 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Nov 27 | Jan 15 | Apr 5 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Phoenix grow?
Each sauce, scheduled for a Phoenix container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Phoenix frost questions
When is the last frost in Phoenix, AZ?
The median last 32 °F freeze at PHOENIX DEER VALLEY MUNI AP, AZ is January 8: half of years see a later one. One year in ten, a freeze still comes after February 12; nine years in ten, it comes after December 16 (prior winter). Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Phoenix, AZ?
The median first 32 °F freeze of fall is December 25. One year in ten it arrives before December 5; nine years in ten, before January 23 (next year).
How long is the growing season in Phoenix, AZ?
354 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 320 days; one year in ten, no freeze at all.
What growing zone is Phoenix, AZ?
USDA hardiness zone 9b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 85021. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Phoenix, AZ?
Start Roma VF (determinate paste) seeds indoors around Nov 27 and transplant around Jan 15, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Feb 12. First ripe fruit lands around Mar 31.
When should I plant peppers in Phoenix, AZ?
Sow jalapeño indoors on a heat mat around Nov 13; transplant no earlier than Jan 15, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Mar 31.
Nearby in Arizona
- Glendalelast frost Jan 20
- Scottsdalelast frost Jan 27
- Tempelast frost Feb 13
- Peorialast frost Feb 5
- Surpriselast frost Feb 5
- Avondalelast frost Jan 7
All Arizona frost dates → · How frost-date math drives a sowing calendar →