Frost Dates & Planting Calendar for San Luis Obispo, CA
Plan your garden around San Luis Obispo, CA's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
January 16
Safe Feb 26
Typical Jan 16
Risky Dec 11
First Fall Frost
December 25
Safe Nov 25
Typical Dec 25
Risky Feb 12
Growing Season
349 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 9b
Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.
Data: NOAA station SAN LUIS OBISPO POLY, CA US, 2.5 km away.
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days until the typical last spring frost
Monthly Temperatures
Avg. high
Avg. temp
Avg. low
Planting Calendar
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Tomato | Nov 21 – Dec 5 | — | Jan 23 – Jan 30 | — | 60–85 days | Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed. |
| Pepper | Nov 7 – Nov 21 | — | Jan 23 – Feb 6 | — | 60–90 days | Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost. |
| Eggplant | Nov 7 – Nov 21 | — | Jan 30 – Feb 6 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Dec 19 – Dec 26 | Jan 23 – Jan 30 | Jan 23 – Jan 30 | — | 50–65 days | Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm. |
| Zucchini | Dec 26 – Jan 2 | Jan 23 – Feb 6 | Jan 23 – Jan 30 | — | 45–55 days | Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start. |
| Winter Squash | Dec 19 – Dec 26 | Jan 23 – Feb 6 | Jan 23 – Jan 30 | — | 80–110 days | Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates. |
| Pumpkin | — | Jan 23 – Feb 6 | — | — | 90–120 days | Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it. |
| Watermelon | Dec 19 – Dec 26 | — | Jan 30 – Feb 6 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Dec 19 – Dec 26 | — | Jan 30 – Feb 6 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Jan 16 – Jan 30 | — | — | 60–100 days | Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks. |
| Green Bean | — | Jan 16 – Jan 30 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Dec 5 – Dec 19 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Dec 19 – Jan 2 | — | Oct 30 – Nov 13 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Dec 5 – Dec 19 | — | Oct 30 – Nov 13 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Dec 19 – Jan 2 | — | Oct 16 – Oct 30 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Dec 19 – Jan 2 | — | Nov 13 – Nov 20 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | Dec 26 – Jan 9 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Nov 28 – Dec 12 | — | Dec 26 – Jan 2 | Oct 23 – Oct 30 | 55–80 days | Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost). |
| Cauliflower | Nov 28 – Dec 12 | — | Jan 2 – Jan 9 | Oct 16 – Oct 23 | 55–85 days | Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost. |
| Cabbage | Nov 28 – Dec 12 | — | Dec 19 – Jan 2 | Oct 16 – Oct 30 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Nov 28 – Dec 12 | — | Dec 26 – Jan 9 | — | 90–110 days | Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost. |
| Carrot | — | Dec 19 – Jan 2 | — | Oct 2 – Oct 16 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | Dec 19 – Jan 2 | — | Oct 16 – Oct 30 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Dec 12 – Dec 26 | — | Nov 13 – Nov 27 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | Dec 19 – Jan 2 | — | Oct 16 – Oct 30 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Nov 7 – Nov 21 | — | Dec 19 – Jan 2 | — | 90–120 days | Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings. |
| Garlic | — | — | — | Nov 27 – Dec 11 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Dec 19 – Jan 2 | — | — | 70–120 days | Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated. |
| Sweet Potato | — | — | Jan 30 – Feb 13 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Dec 19 – Jan 2 | — | 730–1095 days | Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Basil | Dec 5 – Dec 12 | — | Jan 23 – Jan 30 | — | 50–70 days | Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm. |
| Cilantro | — | Dec 26 – Jan 9 | — | Oct 30 – Nov 13 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Nov 21 – Dec 5 | — | Jan 2 – Jan 9 | — | 70–90 days | Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant). |
| Dill | — | Dec 26 – Jan 9 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Nov 21 – Dec 5 | — | Jan 16 – Jan 23 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Nov 21 – Dec 5 | — | Jan 16 – Jan 23 | — | 85–95 days | Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Sunflower | — | Jan 23 – Feb 6 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Dec 19 – Dec 26 | Jan 23 – Feb 6 | Jan 23 – Jan 30 | — | 60–70 days | Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms. |
| Marigold | Dec 5 – Dec 19 | — | Jan 23 – Jan 30 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Dec 19 – Dec 26 | Jan 23 – Feb 6 | Jan 23 – Jan 30 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | Jan 23 – Feb 6 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | Jan 23 – Feb 6 | — | 90–120 days | Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive. |
Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.
Frequently Asked Questions
When is the last frost in San Luis Obispo, CA?
Based on 1991–2020 NOAA climate normals for the SAN LUIS OBISPO POLY, CA US station, the last spring frost in San Luis Obispo typically falls around January 16. A cautious gardener might wait until February 26 (only a 10% chance of a later frost), while December 11 marks an earlier, higher-risk planting date.
When is the first frost in San Luis Obispo, CA in fall?
The first fall frost in San Luis Obispo typically arrives around December 25. To stay safe, assume frost could start as early as November 25; in milder years it can hold off until February 12.
How long is the growing season in San Luis Obispo, CA?
San Luis Obispo's average frost-free growing season is about 349 days, running from the typical last spring frost (January 16) to the typical first fall frost (December 25).
What USDA hardiness zone is San Luis Obispo, CA in?
San Luis Obispo, CA is in USDA plant hardiness zone 9b, per the USDA's 2023 Plant Hardiness Zone Map. Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.