Tucson, AZ Frost Dates & Growing Season

The two dates every Tucson garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Jan 20
~50% chance of frost after
First fall frost
Dec 17
~50% chance of frost before
Growing season
331 days
frost-free stretch
USDA zone
9b
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Dec 19 Jan 20 Feb 18
First fall frost Jan 12 Dec 17 Nov 28
Hard freeze (28°F), median last Jan 4 · first Dec 30

Computed from NOAA 1991–2020 climate normals at the Tucson Wfo station (2 km from central Tucson). "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Tucson

Computed from Tucson's own frost dates. Click any crop for the full zone-9 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Nov 25 – Dec 9 Jan 27 – Feb 3
🫑 Peppers Nov 11 – Nov 25 Feb 3 – Feb 10
🥬 Lettuce Dec 9 – Dec 23 Dec 23 – Jan 6 Dec 23 – Jan 20
🫛 Peas Dec 9 – Dec 23
🥕 Carrots Dec 30 – Jan 20
🥦 Broccoli Dec 2 – Dec 16 Dec 30 – Jan 13
🥬 Kale Dec 9 – Dec 23 Dec 23 – Jan 6 Dec 23 – Jan 6
🥒 Cucumbers Dec 23 – Dec 30 Jan 27 – Feb 3 Jan 27 – Feb 3
🥒 Zucchini Dec 23 – Dec 30 Jan 27 – Feb 3 Jan 27 – Feb 3
🫘 Green Beans (Bush) Jan 27 – Feb 3
🌽 Sweet Corn Jan 27 – Feb 3
🌿 Basil Dec 9 – Dec 23 Jan 27 – Feb 3 Feb 3 – Feb 10
🧄 Garlic Fall: Nov 5 – Dec 3

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Tucson's dates automatically after a lookup.

Reading the season in Tucson

With roughly 331 frost-free days, Tucson gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Dec 17 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Tucson, AZ?

The average last spring frost in Tucson is around Jan 20, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Tucson, AZ?

The average first fall frost in Tucson arrives around Dec 17. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Tucson?

About 331 frost-free days on average, from Jan 20 to Dec 17. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Tucson in?

USDA zone 9b on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.