What planting zone is Honolulu, HI?

Honolulu is in USDA plant hardiness zone 12b (average annual extreme minimum temperature 55 to 60°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Honolulu?

In Honolulu, HI the warmest month is September (avg high 80.8°F) and the coldest is January (avg low 63.1°F). It averages about 151″ of precipitation a year.

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Honolulu, HI Planting Calendar & Frost Dates

USDA hardiness zone 12b · ZIP 96813 · elevation 152′ · NOAA & USDA data

Honolulu sits in USDA zone 12b and is effectively frost-free — you can grow something outdoors year-round. The warmest month is September (avg high 80.8°F) and the coolest is January (avg low 63.1°F). Time plantings by the hot vs. cool season rather than by frost: grow heat-loving crops through the warm months and cool-season greens in the mild winter. The wettest month is July (15.4″).

Hardiness zone

12b

min temp 55 to 60°F

Frost

Frost-free

grow year-round

Warmest month

September

avg high 80.8°F

Month-by-month typical weather in Honolulu

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Manoa Lyon Arbo 785.2, HI (3 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)
January	76	63.1	69.6	10.6
February	75.9	63.3	69.6	9.1
March	75.7	63.9	69.8	13.7
April	76	65.4	70.7	12.9
May	77.7	66.8	72.3	9.3
June	78.1	68.4	73.3	12.9
July	79	69.7	74.4	15.4
August	80.1	70.2	75.2	12.7
September	80.8	70	75.4	12.2
October	80.1	69.2	74.7	12.9
November	78	67.6	72.8	15.1
December	76.4	65.4	70.9	14.2

What to plant when in Honolulu

Honolulu is frost-free, so there's no last-frost date to time from. Grow cool-season crops (lettuce, peas, broccoli, carrots) in the cooler months and warm-season crops (tomatoes, peppers, beans, squash) through the warm season.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Kanalohuluhulu 1075, HI, 129.3 mi (confidence: very-low). Monthly weather normals: Manoa Lyon Arbo 785.2, HI, 3 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.