Merced, California: planting zone & frost dates
Merced is in USDA plant hardiness zone 9a, where the average coldest winter night reaches 20 to 25°F (-6.7 to -3.9°C). The typical last spring frost is around Mar 19 and the first fall frost around Nov 16.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 10 | Nov 5 |
| Typical planning date (30% risk) | Mar 19 | Nov 16 |
| Median (50%) | Mar 3 | Nov 24 |
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 MERCED, CA (USC00045532), 2.4 mi (3.8 km) from the city center and 16 ft lower than the city center (-5 m). Record used for the 1991–2020 normals: 22 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Merced
Merced spans more than one half-zone. Share of the city's land area by zone (via its 3 ZIP codes): 9a (71%), 9b (29%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Merced
Dates are counted from the 30%-risk frost dates above (last frost Mar 19, first frost Nov 16). 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 22 – Feb 5 | Mar 26 – Apr 9 | — | — |
| Pepper | Jan 8 – Jan 22 | Apr 2 – Apr 16 | — | — |
| Lettuce | Feb 5 – Feb 19 | Mar 5 – Mar 26 | Feb 19 – Apr 2 | Sep 7 – Oct 5 |
| Green Beans | — | — | Mar 26 – Apr 30 | Aug 24 – Sep 7 |
| Sweet Corn | — | — | Mar 26 – Apr 23 | — |
| Zucchini & Summer Squash | Feb 19 – Feb 26 | Mar 26 – Apr 9 | Mar 26 – Apr 16 | Aug 24 – Sep 7 |
| Cucumber | Feb 19 – Feb 26 | Apr 2 – Apr 9 | Mar 26 – Apr 16 | Aug 24 – Sep 7 |
| Carrot | — | — | Feb 26 – Apr 2 | Aug 24 – Sep 7 |
| Onion | Dec 25 – Jan 8 | Feb 19 – Mar 5 | — | — |
| Potato | — | Feb 19 – Mar 12 | — | — |
| Basil | Feb 5 – Feb 19 | Apr 2 – Apr 16 | Apr 2 – Apr 23 | — |
| Spinach | — | — | Feb 5 – Mar 5 | Sep 21 – Oct 19 |
| Kale | Jan 22 – Feb 5 | Feb 19 – Mar 12 | Feb 19 – Mar 12 | Sep 7 – Oct 5 |
| Broccoli | Jan 22 – Feb 5 | Mar 5 – Mar 26 | — | Aug 24 – Sep 7 |
| Peas | — | — | Feb 5 – Feb 26 | Sep 7 – Sep 21 |
| Eggplant | Jan 8 – Jan 22 | Apr 2 – Apr 16 | — | — |
| Cabbage | Jan 22 – Feb 5 | Feb 19 – Mar 5 | — | Aug 24 – Sep 7 |
| Radish | — | — | Feb 12 – Apr 2 | Oct 5 – Nov 2 |
| Strawberry | — | Feb 19 – Mar 12 | — | — |
| Beets | — | — | Feb 26 – Apr 9 | Sep 7 – Sep 21 |
Nearby cities in California
- Modesto — zone 9b, last frost Feb 10, first frost Nov 29
- Fresno — zone 9b, last frost Jan 29, first frost Dec 6
- Manteca — zone 9b, last frost Feb 17, first frost Nov 24
- Clovis — zone 9b, last frost Jan 29, first frost Dec 6
- Tracy — zone 9b, last frost Mar 9, first frost Nov 20
- Stockton — zone 9b, last frost Feb 19, first frost Nov 28
More: all California cities · other zone 9a cities: San Antonio, TX, Austin, TX, Seattle, WA, Las Vegas, NV, Portland, OR, Tucson, AZ, Baton Rouge, LA, Tallahassee, FL
Merced gardening questions
When is the last frost in Merced, CA?
Plan around Mar 19. At NOAA's Merced, CA station, 2.4 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 Mar 3, and after Apr 10 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Feb 2. Springs here are erratic: 67 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 Merced, CA?
Start seeds indoors Jan 22 – Feb 5 and set transplants outside Mar 26 – Apr 9, once nights stay above 50°F and the soil is near 60°F. That leaves 242 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 Merced?
About 263 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 226 days, and in 1 year in 10 it runs 303 days or more. In fall there is a 10% chance of frost by Nov 5 and a 30% chance by Nov 16. That ranks 78th longest of 84 California cities on this site.
When should I plant a fall garden in Merced?
Count back from the first fall frost (Nov 16): transplant broccoli Aug 24 – Sep 7; sow kale Sep 7 – Oct 5; sow lettuce Sep 7 – Oct 5; sow radishes Oct 5 – Nov 2. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 11. How the math works: succession and fall planting.
Did Merced's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Merced is zone 9a 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.
Is all of Merced in zone 9a?
No. Zone 9a covers about 71% of the city's land; the rest is in 9b (29%), measured across the city's 3 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.