Tustin Irvine Ranch, CA Frost Dates & Growing Season

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

Last spring frost
Jan 5
~50% chance of frost after
First fall frost
Dec 25
~50% chance of frost before
Growing season
354 days
frost-free stretch
USDA zone
≈ 10b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Dec 14 Jan 5 Feb 2
First fall frost Jan 20 Dec 25 Dec 3

Computed from NOAA 1991–2020 climate normals at the TUSTIN IRVINE RCH station. "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 Tustin Irvine Ranch

Computed from Tustin Irvine Ranch's own frost dates. Click any crop for the full zone-10 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Nov 10 – Nov 24 Jan 12 – Jan 19
🫑 Peppers Oct 27 – Nov 10 Jan 19 – Jan 26
🥬 Lettuce Nov 24 – Dec 8 Dec 8 – Dec 22 Dec 8 – Jan 5
🫛 Peas Nov 24 – Dec 8
🥕 Carrots Dec 15 – Jan 5
🥦 Broccoli Nov 17 – Dec 1 Dec 15 – Dec 29
🥬 Kale Nov 24 – Dec 8 Dec 8 – Dec 22 Dec 8 – Dec 22
🥒 Cucumbers Dec 8 – Dec 15 Jan 12 – Jan 19 Jan 12 – Jan 19
🥒 Zucchini Dec 8 – Dec 15 Jan 12 – Jan 19 Jan 12 – Jan 19
🫘 Green Beans (Bush) Jan 12 – Jan 19
🌽 Sweet Corn Jan 12 – Jan 19
🌿 Basil Nov 24 – Dec 8 Jan 12 – Jan 19 Jan 19 – Jan 26
🧄 Garlic Fall: Nov 13 – Dec 11

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 Tustin Irvine Ranch's dates automatically after a lookup.

Reading the season in Tustin Irvine Ranch

With roughly 354 frost-free days, Tustin Irvine Ranch 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 25 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Tustin Irvine Ranch, CA?

The average last spring frost in Tustin Irvine Ranch is around Jan 5, 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 Tustin Irvine Ranch, CA?

The average first fall frost in Tustin Irvine Ranch arrives around Dec 25. 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 Tustin Irvine Ranch?

About 354 frost-free days on average, from Jan 5 to Dec 25. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Tustin Irvine Ranch in?

USDA zone 10b 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.