Mesa, Arizona: planting zone & frost dates
Mesa is in USDA plant hardiness zone 9b, where the average coldest winter night reaches 25 to 30°F (-3.9 to -1.1°C). The typical last spring frost is around Feb 12 and the first fall frost around Dec 2.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Feb 28 | Nov 22 |
| Typical planning date (30% risk) | Feb 12 | Dec 2 |
| Median (50%) | Feb 1 | Dec 10 |
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 E MESA, AZ (USC00022782), 4.3 mi (7.0 km) from the city center and 190 ft higher than the city center (+58 m). Record used for the 1991–2020 normals: 15 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Mesa
Mesa spans more than one half-zone. Share of the city's land area by zone (via its 13 ZIP codes): 9b (91%), 10a (9%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Mesa
Dates are counted from the 30%-risk frost dates above (last frost Feb 12, first frost Dec 2). 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 18 – Jan 1 | Feb 19 – Mar 5 | — | — |
| Pepper | Dec 4 – Dec 18 | Feb 26 – Mar 12 | — | — |
| Lettuce Mild winters: fall and winter plantings are usually more reliable than spring. | Jan 1 – Jan 15 | Jan 29 – Feb 19 | Jan 15 – Feb 26 | Sep 23 – Oct 21 |
| Green Beans | — | — | Feb 19 – Mar 26 | Sep 9 – Sep 23 |
| Sweet Corn | — | — | Feb 19 – Mar 19 | — |
| Zucchini & Summer Squash | Jan 15 – Jan 22 | Feb 19 – Mar 5 | Feb 19 – Mar 12 | Sep 9 – Sep 23 |
| Cucumber | Jan 15 – Jan 22 | Feb 26 – Mar 5 | Feb 19 – Mar 12 | Sep 9 – Sep 23 |
| Carrot Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 22 – Feb 26 | Sep 9 – Sep 23 |
| Onion Mild winters: fall and winter plantings are usually more reliable than spring. | Nov 20 – Dec 4 | Jan 15 – Jan 29 | — | — |
| Potato Mild winters: fall and winter plantings are usually more reliable than spring. | — | Jan 15 – Feb 5 | — | — |
| Basil | Jan 1 – Jan 15 | Feb 26 – Mar 12 | Feb 26 – Mar 19 | — |
| Spinach Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 1 – Jan 29 | Oct 7 – Nov 4 |
| Kale Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 18 – Jan 1 | Jan 15 – Feb 5 | Jan 15 – Feb 5 | Sep 23 – Oct 21 |
| Broccoli Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 18 – Jan 1 | Jan 29 – Feb 19 | — | Sep 9 – Sep 23 |
| Peas Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 1 – Jan 22 | Sep 23 – Oct 7 |
| Eggplant | Dec 4 – Dec 18 | Feb 26 – Mar 12 | — | — |
| Cabbage Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 18 – Jan 1 | Jan 15 – Jan 29 | — | Sep 9 – Sep 23 |
| Radish Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 8 – Feb 26 | Oct 21 – Nov 18 |
| Strawberry | — | Jan 15 – Feb 5 | — | — |
| Beets Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 22 – Mar 5 | Sep 23 – Oct 7 |
Nearby cities in Arizona
- Gilbert — zone 9b, last frost Feb 12, first frost Dec 3
- Chandler — zone 9b, last frost Feb 24, first frost Nov 29
- Queen Creek — zone 9b, last frost Feb 12, first frost Dec 3
- Tempe — zone 9b, last frost Feb 24, first frost Nov 29
- Scottsdale — zone 10a, last frost Feb 13, first frost Dec 11
- Phoenix — zone 9b, last frost Jan 23, first frost Dec 15
More: all Arizona cities · other zone 9b cities: Houston, TX, Phoenix, AZ, Jacksonville, FL, San Jose, CA, Fresno, CA, Sacramento, CA, Bakersfield, CA, New Orleans, LA
Mesa gardening questions
When is the last frost in Mesa, AZ?
Plan around Feb 12. At NOAA's E Mesa, AZ station, 4.3 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 1, and after Feb 28 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Jan 11. Springs here are erratic: 58 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 Mesa, AZ?
Start seeds indoors Dec 18 – Jan 1 and set transplants outside Feb 19 – Mar 5, once nights stay above 50°F and the soil is near 60°F. With about 293 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 Mesa?
About 312 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 280 days, and in 1 year in 10 it runs 348 days or more. In fall there is a 10% chance of frost by Nov 22 and a 30% chance by Dec 2. That ranks 9th longest of 16 Arizona cities on this site.
When should I plant a fall garden in Mesa?
Count back from the first fall frost (Dec 2): transplant broccoli Sep 9 – Sep 23; sow kale Sep 23 – Oct 21; sow lettuce Sep 23 – Oct 21; sow radishes Oct 21 – Nov 18. 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 Mesa's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Mesa is zone 9b 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 Mesa in zone 9b?
No. Zone 9b covers about 91% of the city's land; the rest is in 10a (9%), measured across the city's 13 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.