Honolulu, Hawaii: planting zone & frost dates
Honolulu is in USDA plant hardiness zone 12b, where the average coldest winter night reaches 55 to 60°F (12.8 to 15.6°C). Frost is rare here.
Frost dates
Frost data comes from NOAA station WAIKIKI 717.2, HI (USC00519397), 4.2 mi (6.7 km) from the city center and 161 ft lower than the city center (-49 m). Record used for the 1991–2020 normals: 18 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Honolulu
All 13 ZIP codes covering Honolulu are in zone 12b.
Vegetable planting calendar for Honolulu
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 Hawaii
More: all Hawaii cities
Honolulu gardening questions
Does it ever frost in Honolulu, HI?
Rarely. From 1991 to 2020, NOAA's Waikiki 717.2, HI station, 4.2 mi from the city center, did not reach 32°F at all — too seldom for NOAA to compute frost dates. Zone 12b means the coldest night of an average winter is 55 to 60°F (12.8 to 15.6°C), so frost is essentially unknown, though cool nights can slow tropical plants.
When should I plant tomatoes in Honolulu, HI?
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 Honolulu?
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 Honolulu's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Honolulu is zone 12b 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.