Frost Dates & Planting Calendar for Simi Valley, CA
Plan your garden around Simi Valley, 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 24
Safe Mar 5
Typical Jan 24
Risky Dec 21
First Fall Frost
December 15
Safe Nov 27
Typical Dec 15
Risky Jan 26
Growing Season
329 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 10a
Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.
Data: NOAA station WOODLAND HILLS PIERCE COLLEGE, CA US, 21.4 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 29 – Dec 13 | — | Jan 31 – Feb 7 | — | 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 15 – Nov 29 | — | Jan 31 – Feb 14 | — | 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 15 – Nov 29 | — | Feb 7 – Feb 14 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Dec 27 – Jan 3 | Jan 31 – Feb 7 | Jan 31 – Feb 7 | — | 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 | Jan 3 – Jan 10 | Jan 31 – Feb 14 | Jan 31 – Feb 7 | — | 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 27 – Jan 3 | Jan 31 – Feb 14 | Jan 31 – Feb 7 | — | 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 31 – Feb 14 | — | — | 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 27 – Jan 3 | — | Feb 7 – Feb 14 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Dec 27 – Jan 3 | — | Feb 7 – Feb 14 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Jan 24 – Feb 7 | — | — | 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 24 – Feb 7 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Dec 13 – Dec 27 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Dec 27 – Jan 10 | — | Oct 20 – Nov 3 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Dec 13 – Dec 27 | — | Oct 20 – Nov 3 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Dec 27 – Jan 10 | — | Oct 6 – Oct 20 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Dec 27 – Jan 10 | — | Nov 3 – Nov 10 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | Jan 3 – Jan 17 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Dec 6 – Dec 20 | — | Jan 3 – Jan 10 | Oct 13 – Oct 20 | 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 | Dec 6 – Dec 20 | — | Jan 10 – Jan 17 | Oct 6 – Oct 13 | 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 | Dec 6 – Dec 20 | — | Dec 27 – Jan 10 | Oct 6 – Oct 20 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Dec 6 – Dec 20 | — | Jan 3 – Jan 17 | — | 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 27 – Jan 10 | — | Sep 22 – Oct 6 | 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 27 – Jan 10 | — | Oct 6 – Oct 20 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Dec 20 – Jan 3 | — | Nov 3 – Nov 17 | 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 27 – Jan 10 | — | Oct 6 – Oct 20 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Nov 15 – Nov 29 | — | Dec 27 – Jan 10 | — | 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 17 – Dec 1 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Dec 27 – Jan 10 | — | — | 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 | — | — | Feb 7 – Feb 21 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Dec 27 – Jan 10 | — | 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 13 – Dec 20 | — | Jan 31 – Feb 7 | — | 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 | — | Jan 3 – Jan 17 | — | Oct 20 – Nov 3 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Nov 29 – Dec 13 | — | Jan 10 – Jan 17 | — | 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 | — | Jan 3 – Jan 17 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Nov 29 – Dec 13 | — | Jan 24 – Jan 31 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Nov 29 – Dec 13 | — | Jan 24 – Jan 31 | — | 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 31 – Feb 14 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Dec 27 – Jan 3 | Jan 31 – Feb 14 | Jan 31 – Feb 7 | — | 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 13 – Dec 27 | — | Jan 31 – Feb 7 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Dec 27 – Jan 3 | Jan 31 – Feb 14 | Jan 31 – Feb 7 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | Jan 31 – Feb 14 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | Jan 31 – Feb 14 | — | 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 Simi Valley, CA?
Based on 1991–2020 NOAA climate normals for the WOODLAND HILLS PIERCE COLLEGE, CA US station, the last spring frost in Simi Valley typically falls around January 24. A cautious gardener might wait until March 5 (only a 10% chance of a later frost), while December 21 marks an earlier, higher-risk planting date.
When is the first frost in Simi Valley, CA in fall?
The first fall frost in Simi Valley typically arrives around December 15. To stay safe, assume frost could start as early as November 27; in milder years it can hold off until January 26.
How long is the growing season in Simi Valley, CA?
Simi Valley's average frost-free growing season is about 329 days, running from the typical last spring frost (January 24) to the typical first fall frost (December 15).
What USDA hardiness zone is Simi Valley, CA in?
Simi Valley, CA is in USDA plant hardiness zone 10a, 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.