Sunnyvale, CA planting zone & frost dates
Sunnyvale is in USDA hardiness zone 10a. The last spring frost usually comes around January 6 and the first fall frost around December 23, for a growing season of about 353 days.
Planting calendar for Sunnyvale
Dates are counted from the average last spring frost (January 6) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Nov 11 – Nov 25 Transplant outdoors: Jan 13 – Jan 20 |
| Peppers | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Jan 20 – Jan 27 |
| Eggplant | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Jan 20 – Jan 27 |
| Broccoli | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Dec 9 – Dec 23 |
| Cabbage | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Dec 9 – Dec 23 |
| Onions (sets) | Plant outdoors: Dec 9 – Dec 23 |
| Peas | Sow outdoors: Nov 25 – Dec 9 |
| Spinach | Sow outdoors: Nov 25 – Dec 9 |
| Lettuce | Sow outdoors: Dec 9 – Dec 23 |
| Carrots | Sow outdoors: Dec 9 – Dec 23 |
| Potatoes | Plant outdoors: Dec 9 – Dec 23 |
| Beans | Sow outdoors: Jan 13 – Jan 20 |
| Sweet corn | Sow outdoors: Jan 13 – Jan 20 |
| Cucumbers | Sow outdoors: Jan 13 – Jan 20 |
| Squash & zucchini | Sow outdoors: Jan 13 – Jan 20 |
| Basil | Start seeds indoors: Nov 25 – Dec 9 Transplant outdoors: Jan 13 – Jan 20 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 28 (8 weeks before the average first fall frost on Dec 23).
Useful for zone 10a gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Shade cloth — for hot summers
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Dec 16 | Jan 6 | Feb 4 |
| First 32°F frost in fall is before | Jan 16 | Dec 23 | Dec 3 |
How to read it: in spring there is a 10% chance of a frost after February 4, so that is a safe date for tender plants. In fall there is a 10% chance of frost before December 3. A hard freeze (28°F) usually ends around January 1.
Hardiness zone by ZIP code in Sunnyvale
- 94085 zone 10a
- 94086 zone 9b
- 94087 zone 9b
- 94088 zone 10a
- 94089 zone 10a
Nearby cities
- Cupertino zone 9b, last frost Jan 6
- Mountain View zone 10a, last frost Jan 6
- Los Altos zone 9b, last frost Jan 6
- Santa Clara zone 9b, last frost Jan 12
- Saratoga zone 9b, last frost Feb 2
- Campbell zone 9b, last frost Feb 2
- Palo Alto zone 9b, last frost Feb 1
- Stanford zone 9b, last frost Feb 1
Questions
What growing zone is Sunnyvale, CA?
Sunnyvale is in USDA Plant Hardiness Zone 10a (average extreme winter low 30°F to 35°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 9b.
When is the last frost in Sunnyvale?
The average last spring frost (32°F) in Sunnyvale is January 6. There is still a 10% chance of frost until February 4.
When can I plant tomatoes in Sunnyvale?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jan 13 – Jan 20. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Moffett Federal Airfield, CA (USW00023244), 4.2 km (2.6 mi) from the city center, elevation 12 m, based on 22 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.