Antioch, CA planting zone & frost dates
Antioch is in USDA hardiness zone 9b. The last spring frost usually comes around January 12 and the first fall frost around December 19, for a growing season of about 343 days.
Planting calendar for Antioch
Dates are counted from the average last spring frost (January 12) 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 17 – Dec 1 Transplant outdoors: Jan 19 – Jan 26 |
| Peppers | Start seeds indoors: Nov 3 – Nov 17 Transplant outdoors: Jan 26 – Feb 2 |
| Eggplant | Start seeds indoors: Nov 3 – Nov 17 Transplant outdoors: Jan 26 – Feb 2 |
| Broccoli | Start seeds indoors: Nov 3 – Nov 17 Transplant outdoors: Dec 15 – Dec 29 |
| Cabbage | Start seeds indoors: Nov 3 – Nov 17 Transplant outdoors: Dec 15 – Dec 29 |
| Onions (sets) | Plant outdoors: Dec 15 – Dec 29 |
| Peas | Sow outdoors: Dec 1 – Dec 15 |
| Spinach | Sow outdoors: Dec 1 – Dec 15 |
| Lettuce | Sow outdoors: Dec 15 – Dec 29 |
| Carrots | Sow outdoors: Dec 15 – Dec 29 |
| Potatoes | Plant outdoors: Dec 15 – Dec 29 |
| Beans | Sow outdoors: Jan 19 – Jan 26 |
| Sweet corn | Sow outdoors: Jan 19 – Jan 26 |
| Cucumbers | Sow outdoors: Jan 19 – Jan 26 |
| Squash & zucchini | Sow outdoors: Jan 19 – Jan 26 |
| Basil | Start seeds indoors: Dec 1 – Dec 15 Transplant outdoors: Jan 19 – Jan 26 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 24 (8 weeks before the average first fall frost on Dec 19).
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Dec 20 | Jan 12 | Feb 1 |
| First 32°F frost in fall is before | Jan 12 | Dec 19 | Nov 29 |
How to read it: in spring there is a 10% chance of a frost after February 1, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 29. A hard freeze (28°F) usually ends around January 2.
Hardiness zone by ZIP code in Antioch
- 94509 zone 9b
- 94531 zone 9b
Nearby cities
- Pittsburg zone 9b, last frost Jan 12
- Oakley zone 9b, last frost Jan 12
- Brentwood zone 9b, last frost Jan 12
- Clayton zone 9b, last frost Jan 9
- Bay Point zone 9b, last frost Jan 9
- Concord zone 9b, last frost Jan 9
- Discovery Bay zone 9b, last frost Jan 19
- Pleasant Hill zone 9b, last frost Jan 7
Questions
What growing zone is Antioch, CA?
Antioch is in USDA Plant Hardiness Zone 9b (average extreme winter low 25°F to 30°F), according to the USDA 2023 map.
When is the last frost in Antioch?
The average last spring frost (32°F) in Antioch is January 12. There is still a 10% chance of frost until February 1.
When can I plant tomatoes in Antioch?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jan 19 – Jan 26. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Antioch Pumping Plt #3, CA (USC00040232), 5.3 km (3.3 mi) from the city center, elevation 18 m, based on 19 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.