State guide
Planting zones in Hawaii
Hawaii spans USDA zones 10b to 13a across its 96 ZIP codes, so there is no single zone for the state and anyone who gives you one is rounding. 64% of its ZIP codes are zone 12b; the rest are not.
Your ZIP code
Get the exact answer for your address
Everything above describes Hawaii as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.
Which zone you are in depends where you are
Hawaii covers 6 hardiness zones. A guide that gives the state one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 64% in zone 12b and wrong for the other 36%. Here is the actual split, by ZIP code.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 12b | 61 | 64% | |
| 12a | 22 | 23% | |
| 11a | 8 | 8% | |
| 11b | 3 | 3% | |
| 10b | 1 | 1% | |
| 13a | 1 | 1% |
Zones are published per ZIP code, so yours is exact even though the state's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
No freeze range is given for Hawaii, and that is the honest answer rather than a missing one. Of its 50 NOAA stations, only 1 has an ordinary freeze window. 48 record no freeze at any probability. 1 sits where the freeze window crosses New Year. A range across the remainder would be a claim about Hawaii built from the small minority of it that behaves like somewhere else.
The single exception is a high-elevation station, and publishing its dates as this state's would be the clearest possible example of one station standing in for a place it does not describe.
Your growing season
NOAA publishes a growing-season length for each station, and across the 50 stations in Hawaii it runs 235–365 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 57–89 °F , below the 90 °F point where cool-season crops reliably bolt.
The ends of each range, named
A range with no station behind it cannot be checked, and Hawaii has too many stations to table them all. So every figure above is reported here with the station standing at each end of it, by name and NOAA ID. No station on this page represents Hawaii — these are its edges, which is a different claim.
| Measure | Earliest / lowest | Station | Latest / highest | Station |
|---|---|---|---|---|
| Growing season | 235 days | Mauna Loa 5 Nne, HI USW00021514 | 365 days | Ewa Kalaeloa AP, HI USW00022551 |
| Mean summer high | 57 °F | Mauna Loa 5 Nne, HI USW00021514 | 89 °F | Kahului AP, HI USW00022516 |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
What survives the winter changes across Hawaii
Of 74 perennial fruits, nuts, berries, vegetables and herbs, 24 come through the winter in zone 10b and only 14 in zone 12a. Winter hardiness runs on the zone alone, so each row below is exact for the ZIP codes in it.
| Zone | ZIPs | Survive | Fail for being too warm |
|---|---|---|---|
| 10b | 1 | 24 of 74 | 50 |
| 11a | 8 | 18 of 74 | 56 |
| 11b | 3 | 18 of 74 | 56 |
| 12a | 22 | 14 of 74 | 60 |
| 12b | 61 | 14 of 74 | 60 |
| 13a | 1 | 14 of 74 | 60 |
The best zone in Hawaii is 10b, which is not its mildest — 13a is. The count peaks in the middle and falls both ways, because the warm end loses plants to insufficient winter chill and summer heat rather than to cold. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the heat that comes with it. See the full list with reasons.
Your own ZIP
Work out your own dates
Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.
- What survives my winter?
Runs on the hardiness zone, so it answers exactly for your ZIP code rather than for Hawaii as a whole — 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Metro areas in Hawaii
2 metro areas here have its own page, with the freeze dates from every station serving it, a spring calendar built from those stations, and every ZIP code in it listed with that ZIP code's exact zone and nearest station.
- Urban Honolulu, HI Zones 12a–13a
- Kahului-Wailuku, HI Zones 11b–12b
Counties in Hawaii
2 countys here have its own page, listing every ZIP code in it with that ZIP code's exact zone and nearest station. These are the smaller places outside the metro areas above — where most of Hawaii's ZIP codes actually are.
- Hawaii County, HI Zones 10b–12b
- Kauai County, HI Zones 12a–12b
Other states to compare
Gear
If you want to act on this
Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.
- Soaker hose and drip kitsThe stations here publish no ordinary freeze window, so frost is not what limits the season — water is, through a summer that does not stop.
As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.
Sources
Where these numbers come from
The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates, growing seasons and summer highs are NOAA's 1991–2020 Climate Normals, read from every station in Hawaii. Which ZIP codes are in Hawaii comes from the Census ZIP-to-county relation, since a county's federal code begins with its state's. Nothing here is estimated.
This page names no single station for Hawaii on purpose. Picking one to represent a state sounds reasonable and is not — the same reason the metro pages refuse it, only more so at this size. Instead every range names the station at each end, so you can check both without either one being made to speak for the state.