Concord Buchanan Field, CA Frost Dates & Growing Season

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

Last spring frost
Jan 9
~50% chance of frost after
First fall frost
Dec 14
~50% chance of frost before
Growing season
339 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 16 Jan 9 Feb 12
First fall frost Jan 16 Dec 14 Nov 28
Hard freeze (28°F), median last Dec 30 · first Dec 23

Computed from NOAA 1991–2020 climate normals at the CONCORD BUCHANAN FLD 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 Concord Buchanan Field

Computed from Concord Buchanan Field'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 14 – Nov 28 Jan 16 – Jan 23
🫑 Peppers Oct 31 – Nov 14 Jan 23 – Jan 30
🥬 Lettuce Nov 28 – Dec 12 Dec 12 – Dec 26 Dec 12 – Jan 9
🫛 Peas Nov 28 – Dec 12
🥕 Carrots Dec 19 – Jan 9
🥦 Broccoli Nov 21 – Dec 5 Dec 19 – Jan 2
🥬 Kale Nov 28 – Dec 12 Dec 12 – Dec 26 Dec 12 – Dec 26
🥒 Cucumbers Dec 12 – Dec 19 Jan 16 – Jan 23 Jan 16 – Jan 23
🥒 Zucchini Dec 12 – Dec 19 Jan 16 – Jan 23 Jan 16 – Jan 23
🫘 Green Beans (Bush) Jan 16 – Jan 23
🌽 Sweet Corn Jan 16 – Jan 23
🌿 Basil Nov 28 – Dec 12 Jan 16 – Jan 23 Jan 23 – Jan 30
🧄 Garlic Fall: Nov 2 – Nov 30

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 Concord Buchanan Field's dates automatically after a lookup.

Reading the season in Concord Buchanan Field

With roughly 339 frost-free days, Concord Buchanan Field 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 14 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Concord Buchanan Field, CA?

The average last spring frost in Concord Buchanan Field is around Jan 9, 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 Concord Buchanan Field, CA?

The average first fall frost in Concord Buchanan Field arrives around Dec 14. 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 Concord Buchanan Field?

About 339 frost-free days on average, from Jan 9 to Dec 14. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Concord Buchanan Field 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.