Tucson, Arizona: planting zone & frost dates
Tucson is in USDA plant hardiness zone 9a, where the average coldest winter night reaches 20 to 25°F (-6.7 to -3.9°C). The typical last spring frost is around Feb 17 and the first fall frost around Nov 30.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Mar 2 | Nov 21 |
| Typical planning date (30% risk) | Feb 17 | Nov 30 |
| Median (50%) | Feb 5 | Dec 9 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station TUCSON INTL AP, AZ (USW00023160), 5.2 mi (8.3 km) from the city center and 148 ft lower than the city center (-45 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Tucson
Tucson spans more than one half-zone. Share of the city's land area by zone (via its 26 ZIP codes): 9a (55%), 9b (45%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
ZIP codes in Tucson and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 85756 | 9a | 21.5% |
| 85747 | 9a | 19.2% |
| 85745 | 9b | 6.3% |
| 85713 | 9b | 5.2% |
| 85710 | 9b | 5.0% |
| 85730 | 9a | 4.4% |
| 85705 | 9b | 4.3% |
| 85706 | 9b | 4.1% |
| 85711 | 9b | 3.6% |
| 85641 | 9a | 3.4% |
| 85719 | 9b | 3.3% |
| 85716 | 9b | 2.9% |
| 85712 | 9b | 2.8% |
| 85748 | 9a | 2.6% |
| 85715 | 9b | 2.1% |
| 85714 | 9b | 1.8% |
| 85707 | 9b | 1.7% |
| 85746 | 9a | 1.5% |
| 85708 | 9b | 1.2% |
| 85749 | 9a | 1.2% |
| 85701 | 9b | 0.6% |
| 85734 | 9a | 0.5% |
| 85709 | 9b | 0.2% |
| 85723 | 9b | 0.1% |
| 85724 | 9b | 0.0% |
| 85726 | 9b | 0.0% |
Vegetable planting calendar for Tucson
Dates are counted from the 30%-risk frost dates above (last frost Feb 17, first frost Nov 30). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Dec 23 – Jan 6 | Feb 24 – Mar 10 | — | — |
| Pepper | Dec 9 – Dec 23 | Mar 3 – Mar 17 | — | — |
| Lettuce Mild winters: fall and winter plantings are usually more reliable than spring. | Jan 6 – Jan 20 | Feb 3 – Feb 24 | Jan 20 – Mar 3 | Sep 21 – Oct 19 |
| Green Beans | — | — | Feb 24 – Mar 31 | Sep 7 – Sep 21 |
| Sweet Corn | — | — | Feb 24 – Mar 24 | — |
| Zucchini & Summer Squash | Jan 20 – Jan 27 | Feb 24 – Mar 10 | Feb 24 – Mar 17 | Sep 7 – Sep 21 |
| Cucumber | Jan 20 – Jan 27 | Mar 3 – Mar 10 | Feb 24 – Mar 17 | Sep 7 – Sep 21 |
| Carrot Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 27 – Mar 3 | Sep 7 – Sep 21 |
| Onion Mild winters: fall and winter plantings are usually more reliable than spring. | Nov 25 – Dec 9 | Jan 20 – Feb 3 | — | — |
| Potato Mild winters: fall and winter plantings are usually more reliable than spring. | — | Jan 20 – Feb 10 | — | — |
| Basil | Jan 6 – Jan 20 | Mar 3 – Mar 17 | Mar 3 – Mar 24 | — |
| Spinach Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 6 – Feb 3 | Oct 5 – Nov 2 |
| Kale Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 23 – Jan 6 | Jan 20 – Feb 10 | Jan 20 – Feb 10 | Sep 21 – Oct 19 |
| Broccoli Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 23 – Jan 6 | Feb 3 – Feb 24 | — | Sep 7 – Sep 21 |
| Peas Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 6 – Jan 27 | Sep 21 – Oct 5 |
| Eggplant | Dec 9 – Dec 23 | Mar 3 – Mar 17 | — | — |
| Cabbage Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 23 – Jan 6 | Jan 20 – Feb 3 | — | Sep 7 – Sep 21 |
| Radish Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 13 – Mar 3 | Oct 19 – Nov 16 |
| Strawberry | — | Jan 20 – Feb 10 | — | — |
| Beets Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 27 – Mar 10 | Sep 21 – Oct 5 |
Nearby cities in Arizona
- Queen Creek — zone 9b, last frost Feb 12, first frost Dec 3
- Maricopa — zone 9a, last frost Mar 3, first frost Nov 18
- Gilbert — zone 9b, last frost Feb 12, first frost Dec 3
- Chandler — zone 9b, last frost Feb 24, first frost Nov 29
- Mesa — zone 9b, last frost Feb 12, first frost Dec 2
- Tempe — zone 9b, last frost Feb 24, first frost Nov 29
More: all Arizona cities · other zone 9a cities: San Antonio, TX, Austin, TX, Seattle, WA, Las Vegas, NV, Portland, OR, Baton Rouge, LA, Tallahassee, FL, Mobile, AL
Tucson gardening questions
When is the last frost in Tucson, AZ?
Plan around Feb 17. At NOAA's Tucson Int'l Airport, AZ station, 5.2 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Feb 5, and after Mar 2 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Jan 11. Springs here are erratic: 57 days separate the 90% and 10% dates, versus a median of 36 days for cities on this site, so watch the forecast rather than the calendar.
When should I plant tomatoes in Tucson, AZ?
Start seeds indoors Dec 23 – Jan 6 and set transplants outside Feb 24 – Mar 10, once nights stay above 50°F and the soil is near 60°F. With about 286 frost-free days, frost is not the main limit — fruit set drops when nights stay above about 75°F, so early plantings tend to do best. More: tomato planting dates by zone.
How long is the growing season in Tucson?
About 307 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 274 days, and in 1 year in 10 it runs 344 days or more. In fall there is a 10% chance of frost by Nov 21 and a 30% chance by Nov 30. That ranks 10th longest of 16 Arizona cities on this site.
When should I plant a fall garden in Tucson?
Count back from the first fall frost (Nov 30): transplant broccoli Sep 7 – Sep 21; sow kale Sep 21 – Oct 19; sow lettuce Sep 21 – Oct 19; sow radishes Oct 19 – Nov 16. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 26. How the math works: succession and fall planting.
Did Tucson's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Tucson is zone 9a on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
Is all of Tucson in zone 9a?
No. Zone 9a covers about 55% of the city's land; the rest is in 9b (45%), measured across the city's 26 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.