Honolulu, Hawaii Frost Dates & Planting Calendar
Honolulu is located in Hawaii at an elevation of 13 feet. The city falls within USDA plant hardiness zone 11b, where average annual extreme minimum winter temperatures range from 45 to 50 degrees Fahrenheit. Honolulu is essentially frost-free, enjoying year-round growing conditions that support tropical and subtropical plants.
Frost Date Summary for Honolulu
Last Spring Frost
January 1
This is the average date of the last freezing temperature (32 degrees F or below) in spring. After this date, it is generally safe to transplant frost-tender seedlings outdoors. In any given year, the actual last frost may occur one to three weeks earlier or later.
First Fall Frost
December 31
This is the average date of the first freezing temperature in autumn. Frost-sensitive crops must be harvested before this date, or protected with row covers and frost blankets. Plan your fall garden so crops mature well before this date.
Growing Season
365 days
The number of frost-free days between the average last spring frost and first fall frost. When choosing crop varieties, compare their "days to maturity" against your growing season length to ensure they have time to produce a harvest.
Hardiness Zone
Zone 11b
USDA hardiness zone based on average annual extreme minimum temperature of 45 degrees F. Perennial plants, trees, and shrubs rated for zone 11b or lower should survive winter here. Learn more about zone 11.
Planting Calendar for Honolulu
These recommended planting dates are calculated from Honolulu's average frost dates. Adjust based on current weather conditions and forecasts.
November 13
Start warm-season seeds (tomatoes, peppers, eggplant) indoors under grow lights approximately seven weeks before the average last frost. This gives transplants time to develop strong root systems before going outside.
January 15
Two weeks after the average last frost date, soil and air temperatures should be warm enough for transplanting hardened-off seedlings. Check the 10-day forecast before committing tender plants to the ground.
October 22
The last practical date to direct-sow fall crops like beans, squash, and quick-maturing greens so they mature before the average first fall frost. Choose fast-maturing varieties for late plantings.
Monthly Gardening Timeline
Below is a general month-by-month overview of garden activities for Honolulu, based on its 365-day growing season and zone 11b climate. Specific tasks depend on your exact crops and gardening style.
| Month | Activity |
|---|---|
| January | Harvest cool-season crops. Maintain tropical plantings. Prune dormant trees. |
| February | Harvest cool-season crops. Maintain tropical plantings. Prune dormant trees. |
| March | Plant warm-season crops. Succession-plant beans, squash, and cucumbers. |
| April | Plant warm-season crops. Succession-plant beans, squash, and cucumbers. |
| May | Plant warm-season crops. Succession-plant beans, squash, and cucumbers. |
| June | Maintain summer garden. Harvest warm-season crops. Water deeply in heat. |
| July | Maintain summer garden. Harvest warm-season crops. Water deeply in heat. |
| August | Maintain summer garden. Harvest warm-season crops. Water deeply in heat. |
| September | Maintain summer garden. Harvest warm-season crops. Water deeply in heat. |
| October | Plant cool-season crops. Harvest tropical fruits. Plan winter garden. |
| November | Plant cool-season crops. Harvest tropical fruits. Plan winter garden. |
| December | Plant cool-season crops. Harvest tropical fruits. Plan winter garden. |
What to Grow in Honolulu (Zone 11b)
With 365 frost-free days and minimum winter temperatures around 45 degrees Fahrenheit, Honolulu supports a year-round range of edible and ornamental plants. Selecting varieties matched to your season length ensures the best results.
Warm-Season Vegetables
Tomatoes, peppers, eggplant, okra, sweet potatoes, tropical fruits like mangos, papayas, and bananas can be grown year-round. Multiple successions of beans, squash, and cucumbers are possible throughout the year.
Cool-Season Vegetables
Traditional cool-season crops like lettuce, spinach, broccoli, and peas grow best during the cooler winter months when temperatures moderate. Plan these for November through March plantings.
Perennial Edibles & Fruit
Citrus trees, avocados, figs, bananas, and tropical ornamentals thrive without winter protection. Herb gardens with rosemary, basil, and lemongrass produce year-round.
Zone 11b Details for Honolulu
Temperature Range: 45°F to 50°F average annual extreme minimum
Description: Tropical Hawaii; no frost risk
Elevation: Honolulu sits at 13 feet, which influences both frost timing and growing conditions. Higher elevations within zone 11b may experience slightly later spring frosts and earlier fall frosts than lower-elevation locations in the same zone.
Frost Protection Tips for Honolulu Gardeners
Honolulu's frost-free climate means you rarely need to worry about freeze protection. However, on the rare occasions when temperatures approach freezing, cover tropical plants with frost cloth and bring potted tropicals indoors. The primary challenges in your climate are heat management, water conservation, and pest control rather than frost protection.
Other Cities in Hawaii
Compare frost dates and growing conditions across Hawaii: