San Diego Brown Field, CA Frost Dates & Growing Season

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

Last spring frost
Jan 6
~50% chance of frost after
First fall frost
Dec 31
~50% chance of frost before
Growing season
359 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 13 Jan 6 Feb 5
First fall frost Jan 30 Dec 31 Dec 11

Computed from NOAA 1991–2020 climate normals at the SAN DIEGO BROWN 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 San Diego Brown Field

Computed from San Diego Brown 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 11 – Nov 25 Jan 13 – Jan 20
🫑 Peppers Oct 28 – Nov 11 Jan 20 – Jan 27
🥬 Lettuce Nov 25 – Dec 9 Dec 9 – Dec 23 Dec 9 – Jan 6
🫛 Peas Nov 25 – Dec 9
🥕 Carrots Dec 16 – Jan 6
🥦 Broccoli Nov 18 – Dec 2 Dec 16 – Dec 30
🥬 Kale Nov 25 – Dec 9 Dec 9 – Dec 23 Dec 9 – Dec 23
🥒 Cucumbers Dec 9 – Dec 16 Jan 13 – Jan 20 Jan 13 – Jan 20
🥒 Zucchini Dec 9 – Dec 16 Jan 13 – Jan 20 Jan 13 – Jan 20
🫘 Green Beans (Bush) Jan 13 – Jan 20
🌽 Sweet Corn Jan 13 – Jan 20
🌿 Basil Nov 25 – Dec 9 Jan 13 – Jan 20 Jan 20 – Jan 27
🧄 Garlic Fall: Nov 19 – Dec 17

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 San Diego Brown Field's dates automatically after a lookup.

Reading the season in San Diego Brown Field

With roughly 359 frost-free days, San Diego Brown 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 31 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in San Diego Brown Field, CA?

The average last spring frost in San Diego Brown Field is around Jan 6, 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 San Diego Brown Field, CA?

The average first fall frost in San Diego Brown Field arrives around Dec 31. 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 San Diego Brown Field?

About 359 frost-free days on average, from Jan 6 to Dec 31. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is San Diego Brown 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.