Milpitas, California: planting zone & frost dates
Milpitas is in USDA plant hardiness zone 10a, where the average coldest winter night reaches 30 to 35°F (-1.1 to 1.7°C). The typical last spring frost is around Jan 26 and the first fall frost around Dec 12.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Feb 14 | Dec 1 |
| Typical planning date (30% risk) | Jan 26 | Dec 12 |
| Median (50%) | Jan 12 | Dec 22 |
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 SAN JOSE, CA (USW00023293), 5.4 mi (8.7 km) from the city center and 16 ft higher than the city center (+5 m). Record used for the 1991–2020 normals: 21 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Milpitas
All 1 ZIP code covering Milpitas is in zone 10a.
ZIP codes in Milpitas and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 95035 | 10a | 99.8% |
Vegetable planting calendar for Milpitas
Dates are counted from the 30%-risk frost dates above (last frost Jan 26, first frost Dec 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 | Dec 1 – Dec 15 | Feb 2 – Feb 16 | — | — |
| Pepper | Nov 17 – Dec 1 | Feb 9 – Feb 23 | — | — |
| Lettuce Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 15 – Dec 29 | Jan 12 – Feb 2 | Dec 29 – Feb 9 | Oct 3 – Oct 31 |
| Green Beans | — | — | Feb 2 – Mar 9 | Sep 19 – Oct 3 |
| Sweet Corn | — | — | Feb 2 – Mar 2 | — |
| Zucchini & Summer Squash | Dec 29 – Jan 5 | Feb 2 – Feb 16 | Feb 2 – Feb 23 | Sep 19 – Oct 3 |
| Cucumber | Dec 29 – Jan 5 | Feb 9 – Feb 16 | Feb 2 – Feb 23 | Sep 19 – Oct 3 |
| Carrot Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 5 – Feb 9 | Sep 19 – Oct 3 |
| Onion Mild winters: fall and winter plantings are usually more reliable than spring. | Nov 3 – Nov 17 | Dec 29 – Jan 12 | — | — |
| Potato Mild winters: fall and winter plantings are usually more reliable than spring. | — | Dec 29 – Jan 19 | — | — |
| Basil | Dec 15 – Dec 29 | Feb 9 – Feb 23 | Feb 9 – Mar 2 | — |
| Spinach Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Dec 15 – Jan 12 | Oct 17 – Nov 14 |
| Kale Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 1 – Dec 15 | Dec 29 – Jan 19 | Dec 29 – Jan 19 | Oct 3 – Oct 31 |
| Broccoli Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 1 – Dec 15 | Jan 12 – Feb 2 | — | Sep 19 – Oct 3 |
| Peas Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Dec 15 – Jan 5 | Oct 3 – Oct 17 |
| Eggplant | Nov 17 – Dec 1 | Feb 9 – Feb 23 | — | — |
| Cabbage Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 1 – Dec 15 | Dec 29 – Jan 12 | — | Sep 19 – Oct 3 |
| Radish Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Dec 22 – Feb 9 | Oct 31 – Nov 28 |
| Strawberry | — | Dec 29 – Jan 19 | — | — |
| Beets Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 5 – Feb 16 | Oct 3 – Oct 17 |
Nearby cities in California
- Fremont — zone 9b, last frost Jan 8, first frost Dec 19
- Santa Clara — zone 9b, last frost Jan 26, first frost Dec 12
- Sunnyvale — zone 9b, last frost Jan 18, first frost Dec 15
- San Jose — zone 9b, last frost Jan 10, first frost Dec 14
- Mountain View — zone 10a, last frost Jan 18, first frost Dec 15
- Livermore — zone 9b, last frost Feb 28, first frost Nov 25
More: all California cities · other zone 10a cities: Los Angeles, CA, Oakland, CA, Tampa, FL, Orlando, FL, Riverside, CA, Corpus Christi, TX, Port St. Lucie, FL, Scottsdale, AZ
Milpitas gardening questions
When is the last frost in Milpitas, CA?
Plan around Jan 26. At NOAA's San Jose, CA station, 5.4 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 Jan 12, and after Feb 14 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Dec 31. Springs here are erratic: 56 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 Milpitas, CA?
Start seeds indoors Dec 1 – Dec 15 and set transplants outside Feb 2 – Feb 16, once nights stay above 50°F and the soil is near 60°F. With about 320 frost-free days, frost is not the main limit — fruit set drops when nights stay above about 75°F, so early plantings tend to do best. More: tomato planting dates by zone.
How long is the growing season in Milpitas?
About 347 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 313 days, and in 1 year in 10 it runs 365 days or more. In fall there is a 10% chance of frost by Dec 1 and a 30% chance by Dec 12. That ranks 39th longest of 84 California cities on this site.
When should I plant a fall garden in Milpitas?
Count back from the first fall frost (Dec 12): transplant broccoli Sep 19 – Oct 3; sow kale Oct 3 – Oct 31; sow lettuce Oct 3 – Oct 31; sow radishes Oct 31 – Nov 28. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 28. How the math works: succession and fall planting.
Did Milpitas's hardiness zone change on the 2023 map?
Yes. Most of Milpitas was zone 9b on the 2012 map and is zone 10a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Milpitas compare with Fremont, CA?
Milpitas is zone 10a and Fremont is zone 9b. The typical last spring frost in Milpitas (Jan 26) comes about 18 days later than in Fremont, CA (Jan 8), 5 miles away, and the first fall frost is Dec 12 versus Dec 19. The two cities use different NOAA stations.