San Luis Dam, CA Frost Dates & Growing Season

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

Last spring frost
Jan 27
~50% chance of frost after
First fall frost
Dec 11
~50% chance of frost before
Growing season
318 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 31 Jan 27 Feb 22
First fall frost Jan 6 Dec 11 Nov 25
Hard freeze (28°F), median last Jan 6 · first Dec 24

Computed from NOAA 1991–2020 climate normals at the SAN LUIS DAM 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 Luis Dam

Computed from San Luis Dam'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 Dec 2 – Dec 16 Feb 3 – Feb 10
🫑 Peppers Nov 18 – Dec 2 Feb 10 – Feb 17
🥬 Lettuce Dec 16 – Dec 30 Dec 30 – Jan 13 Dec 30 – Jan 27
🫛 Peas Dec 16 – Dec 30
🥕 Carrots Jan 6 – Jan 27
🥦 Broccoli Dec 9 – Dec 23 Jan 6 – Jan 20
🥬 Kale Dec 16 – Dec 30 Dec 30 – Jan 13 Dec 30 – Jan 13
🥒 Cucumbers Dec 30 – Jan 6 Feb 3 – Feb 10 Feb 3 – Feb 10
🥒 Zucchini Dec 30 – Jan 6 Feb 3 – Feb 10 Feb 3 – Feb 10
🫘 Green Beans (Bush) Feb 3 – Feb 10
🌽 Sweet Corn Feb 3 – Feb 10
🌿 Basil Dec 16 – Dec 30 Feb 3 – Feb 10 Feb 10 – Feb 17
🧄 Garlic Fall: Oct 30 – Nov 27

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 Luis Dam's dates automatically after a lookup.

Reading the season in San Luis Dam

With roughly 318 frost-free days, San Luis Dam 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 11 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in San Luis Dam, CA?

The average last spring frost in San Luis Dam is around Jan 27, 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 Luis Dam, CA?

The average first fall frost in San Luis Dam arrives around Dec 11. 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 Luis Dam?

About 318 frost-free days on average, from Jan 27 to Dec 11. 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 Luis Dam 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.