Tustin, California: planting zone & frost dates
Tustin is in USDA plant hardiness zone 10a, where the average coldest winter night reaches 30 to 35°F (-1.1 to 1.7°C). Frost is rare here.
Frost dates
Frost data comes from NOAA station SANTA ANA FIRE STN, CA (USC00047888), 3.4 mi (5.4 km) from the city center and 39 ft higher than the city center (+12 m). Record used for the 1991–2020 normals: 28 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Tustin
Tustin spans more than one half-zone. Share of the city's land area by zone (via its 3 ZIP codes): 10a (95%), 10b (5%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Tustin
Windows below are for a frost-free climate: plant cool-season crops from fall through late winter and warm-season crops in late winter–spring, with a second warm-season round in late summer for some crops.
| Crop | Planting windows (frost-free climate) | |||
|---|---|---|---|---|
| Tomato | Jan 15 – Mar 31; Aug 1 – Sep 15 | |||
| Pepper | Feb 1 – Apr 15; Jul 15 – Aug 31 | |||
| Lettuce | Sep 15 – Feb 15 | |||
| Green Beans | Feb 15 – Apr 30; Aug 15 – Sep 30 | |||
| Sweet Corn | Feb 15 – Apr 15; Aug 1 – Aug 31 | |||
| Zucchini & Summer Squash | Feb 15 – Apr 15; Aug 1 – Sep 15 | |||
| Cucumber | Feb 15 – Apr 15; Aug 1 – Sep 15 | |||
| Carrot | Sep 1 – Feb 28 | |||
| Onion | Oct 15 – Jan 15 | |||
| Potato | Jan 1 – Feb 28; Sep 1 – Oct 15 | |||
| Basil | Mar 1 – Jun 30; Aug 15 – Sep 30 | |||
| Spinach | Oct 1 – Feb 15 | |||
| Kale | Sep 1 – Feb 15 | |||
| Broccoli | Sep 1 – Jan 15 | |||
| Peas | Oct 1 – Jan 31 | |||
| Eggplant | Feb 15 – Apr 30; Jul 15 – Aug 31 | |||
| Cabbage | Sep 1 – Jan 31 | |||
| Radish | Sep 15 – Mar 15 | |||
| Strawberry | Oct 1 – Nov 30 | |||
| Beets | Sep 15 – Feb 28 | |||
Nearby cities in California
- Irvine — zone 10b, last frost Jan 14, first frost Dec 13
- Santa Ana — zone 10b, frost rare
- Orange — zone 10b, frost rare
- Costa Mesa — zone 10b, frost rare
- Anaheim — zone 10b, frost rare
- Lake Forest — zone 10b, frost rare
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
Tustin gardening questions
Does it ever frost in Tustin, CA?
Rarely. From 1991 to 2020, NOAA's Santa Ana Fire Stn, CA station, 3.4 mi from the city center, reached 32°F in only 2% of years — too seldom for NOAA to compute frost dates. Zone 10a means the coldest night of an average winter is 30 to 35°F (-1.1 to 1.7°C), so tender plants may still need covering in an unusual cold snap.
When should I plant tomatoes in Tustin, CA?
Without a frost season, plant by temperature: set out tomatoes Jan 15 – Mar 31 and Aug 1 – Sep 15. Fruit set drops when nights stay above about 75°F, so avoid timing harvests for the hottest weeks. More: tomato planting by zone.
When is the best time for lettuce and broccoli in Tustin?
Cool-season crops do best in the mild months: plant lettuce Sep 15 – Feb 15 and broccoli Sep 1 – Jan 15. Summer heat makes lettuce bolt and broccoli flower early.
Did Tustin's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Tustin is zone 10a 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 Tustin in zone 10a?
No. Zone 10a covers about 95% of the city's land; the rest is in 10b (5%), measured across the city's 3 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.
How does Tustin compare with Irvine, CA?
Tustin is zone 10a and Irvine is zone 10b. Frost is rare in Tustin, but Irvine (4 miles away) has a typical last frost around Jan 14 — see Irvine, CA.