Pomona-Fairplex, CA Frost Dates & Growing Season

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

Last spring frost
Jan 8
~50% chance of frost after
First fall frost
Dec 28
~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 8 Feb 18
First fall frost Feb 2 Dec 28 Dec 5

Computed from NOAA 1991–2020 climate normals at the POMONA/FAIRPLEX 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 Pomona-Fairplex

Computed from Pomona-Fairplex'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 13 – Nov 27 Jan 15 – Jan 22
🫑 Peppers Oct 30 – Nov 13 Jan 22 – Jan 29
🥬 Lettuce Nov 27 – Dec 11 Dec 11 – Dec 25 Dec 11 – Jan 8
🫛 Peas Nov 27 – Dec 11
🥕 Carrots Dec 18 – Jan 8
🥦 Broccoli Nov 20 – Dec 4 Dec 18 – Jan 1
🥬 Kale Nov 27 – Dec 11 Dec 11 – Dec 25 Dec 11 – Dec 25
🥒 Cucumbers Dec 11 – Dec 18 Jan 15 – Jan 22 Jan 15 – Jan 22
🥒 Zucchini Dec 11 – Dec 18 Jan 15 – Jan 22 Jan 15 – Jan 22
🫘 Green Beans (Bush) Jan 15 – Jan 22
🌽 Sweet Corn Jan 15 – Jan 22
🌿 Basil Nov 27 – Dec 11 Jan 15 – Jan 22 Jan 22 – Jan 29
🧄 Garlic Fall: Nov 16 – Dec 14

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 Pomona-Fairplex's dates automatically after a lookup.

Reading the season in Pomona-Fairplex

With roughly 354 frost-free days, Pomona-Fairplex 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 28 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Pomona-Fairplex, CA?

The average last spring frost in Pomona-Fairplex is around Jan 8, 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 Pomona-Fairplex, CA?

The average first fall frost in Pomona-Fairplex arrives around Dec 28. 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 Pomona-Fairplex?

About 354 frost-free days on average, from Jan 8 to Dec 28. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Pomona-Fairplex 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.