Vallejo, California: planting zone & frost dates
Vallejo is in USDA plant hardiness zone 9b, where the average coldest winter night reaches 25 to 30°F (-3.9 to -1.1°C). The typical last spring frost is around Mar 25 and the first fall frost around Nov 12.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 16 | Nov 3 |
| Typical planning date (30% risk) | Mar 25 | Nov 12 |
| Median (50%) | Mar 5 | Nov 21 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station NAPA CO AP, CA (USW00093227), 7.3 mi (11.7 km) from the city center and 79 ft lower than the city center (-24 m). Record used for the 1991–2020 normals: 21 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Vallejo
All 4 ZIP codes covering Vallejo are in zone 9b.
Vegetable planting calendar for Vallejo
Dates are counted from the 30%-risk frost dates above (last frost Mar 25, first frost Nov 12). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Jan 28 – Feb 11 | Apr 1 – Apr 15 | — | — |
| Pepper | Jan 14 – Jan 28 | Apr 8 – Apr 22 | — | — |
| Lettuce | Feb 11 – Feb 25 | Mar 11 – Apr 1 | Feb 25 – Apr 8 | Sep 3 – Oct 1 |
| Green Beans | — | — | Apr 1 – May 6 | Aug 20 – Sep 3 |
| Sweet Corn | — | — | Apr 1 – Apr 29 | — |
| Zucchini & Summer Squash | Feb 25 – Mar 4 | Apr 1 – Apr 15 | Apr 1 – Apr 22 | Aug 20 – Sep 3 |
| Cucumber | Feb 25 – Mar 4 | Apr 8 – Apr 15 | Apr 1 – Apr 22 | Aug 20 – Sep 3 |
| Carrot | — | — | Mar 4 – Apr 8 | Aug 20 – Sep 3 |
| Onion | Dec 31 – Jan 14 | Feb 25 – Mar 11 | — | — |
| Potato | — | Feb 25 – Mar 18 | — | — |
| Basil | Feb 11 – Feb 25 | Apr 8 – Apr 22 | Apr 8 – Apr 29 | — |
| Spinach | — | — | Feb 11 – Mar 11 | Sep 17 – Oct 15 |
| Kale | Jan 28 – Feb 11 | Feb 25 – Mar 18 | Feb 25 – Mar 18 | Sep 3 – Oct 1 |
| Broccoli | Jan 28 – Feb 11 | Mar 11 – Apr 1 | — | Aug 20 – Sep 3 |
| Peas | — | — | Feb 11 – Mar 4 | Sep 3 – Sep 17 |
| Eggplant | Jan 14 – Jan 28 | Apr 8 – Apr 22 | — | — |
| Cabbage | Jan 28 – Feb 11 | Feb 25 – Mar 11 | — | Aug 20 – Sep 3 |
| Radish | — | — | Feb 18 – Apr 8 | Oct 1 – Oct 29 |
| Strawberry | — | Feb 25 – Mar 18 | — | — |
| Beets | — | — | Mar 4 – Apr 15 | Sep 3 – Sep 17 |
Nearby cities in California
- Richmond — zone 10a, last frost Jan 14, first frost Dec 27
- Napa — zone 9b, last frost Feb 27, first frost Nov 28
- Berkeley — zone 10a, last frost Jan 12, first frost Dec 25
- Fairfield — zone 9b, last frost Jan 28, first frost Dec 7
- Concord — zone 9b, last frost Jan 23, first frost Dec 6
- Oakland — zone 10a, frost rare
More: all California cities · other zone 9b cities: Houston, TX, Phoenix, AZ, Jacksonville, FL, San Jose, CA, Fresno, CA, Sacramento, CA, Mesa, AZ, Bakersfield, CA
Vallejo gardening questions
When is the last frost in Vallejo, CA?
Plan around Mar 25. At NOAA's Napa County Airport, CA station, 7.3 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Mar 5, and after Apr 16 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Jan 23. Springs here are erratic: 80 days separate the 90% and 10% dates, versus a median of 36 days for cities on this site, so watch the forecast rather than the calendar.
When should I plant tomatoes in Vallejo, CA?
Start seeds indoors Jan 28 – Feb 11 and set transplants outside Apr 1 – Apr 15, once nights stay above 50°F and the soil is near 60°F. That leaves 232 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Vallejo?
About 256 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 212 days, and in 1 year in 10 it runs 305 days or more. In fall there is a 10% chance of frost by Nov 3 and a 30% chance by Nov 12. That ranks 81st longest of 84 California cities on this site.
When should I plant a fall garden in Vallejo?
Count back from the first fall frost (Nov 12): transplant broccoli Aug 20 – Sep 3; sow kale Sep 3 – Oct 1; sow lettuce Sep 3 – Oct 1; sow radishes Oct 1 – Oct 29. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 5. How the math works: succession and fall planting.
Did Vallejo's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Vallejo is zone 9b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Vallejo compare with Richmond, CA?
Vallejo is zone 9b and Richmond is zone 10a. The typical last spring frost in Vallejo (Mar 25) comes about 70 days later than in Richmond, CA (Jan 14), 12 miles away, and the first fall frost is Nov 12 versus Dec 27. The two cities use different NOAA stations.