Hawaii weather and outdoor projects
Hawaii is warm all year, and the main difference is between the wet windward sides of the islands and the drier leeward sides. Hilo on the windward side of the Big Island is one of the wettest cities in the U.S., while Honolulu on Oahu’s leeward side is much drier. Where you are on the island matters more than the month.
The trade winds blow most days, so wind can matter for spraying paint or weed killer. The wetter season runs roughly October to April. Strong sun, salt air and constant warmth break down finishes quickly, so plan on more frequent maintenance coats than on the mainland.
Frost dates in Hawaii
Honolulu almost never freezes on average, so frost rarely limits outdoor projects there, though a cold snap can still bring a freezing night.
Hilo almost never freezes on average, so frost rarely limits outdoor projects there, though a cold snap can still bring a freezing night.
How Hawaii compares with other states
Honolulu is tied for the longest frost-free season of the 50 state main stations (almost no frost). Honolulu is tied for the fewest freezing nights of the 50 state main stations (0 a year). Honolulu has the 2nd-longest deck staining season of the 50 state main stations (9 good months).
| Measure (Honolulu) | Value | Rank, highest first |
|---|---|---|
| Deck staining season | 9 good months | 2nd of 50 |
| Frost-free season | almost no frost | 1st of 50 |
| Freezing nights | 0 a year | 48th of 50 |
| Rainy days | 27 a year with 0.1 in or more | 46th of 50 |
| Days at 90°F or hotter | 32 a year | 24th of 50 |
| Summer afternoons | 52% humidity at 3 PM, June–August | 15th of 47 |
Best time to stain a deck in Hawaii
In Honolulu, the most reliable months are October–June. July–September can also work on the right days (average highs Jul 88°F, Aug 89°F, Sep 88°F). July–September is hot, with highs near 88°F, so start early and keep out of full afternoon sun.
Hilo has no month that is easy for this job on average; the best chances come in January–February. March–December averages about 17 days a month with a tenth of an inch of rain or more, which makes long dry stretches hard to find. January–February averages about 10 wet days a month, so wait for a clear stretch.
Best time to paint outside in Hawaii
In Honolulu, the most reliable months are October–June. July–September can also work on the right days (average highs Jul 88°F, Aug 89°F, Sep 88°F). July–September is hot, with highs near 88°F, so start early and keep out of full afternoon sun.
Hilo has no month that is easy for this job on average; the best chances come in January–February. March–December averages about 17 days a month with a tenth of an inch of rain or more, which makes long dry stretches hard to find. January–February averages about 10 wet days a month, so wait for a clear stretch.
Best time to pour concrete in Hawaii
In Honolulu, a typical month suits this job all year round.
In Hilo, the most reliable months are January–February. March–December can also work on the right days. March–December averages about 17 wet days a month, so wait for a clear stretch.
Best time to seal a driveway in Hawaii
In Honolulu, a typical month suits this job all year round.
Hilo has no month that is easy for this job on average; the best chances come in January–February. March–December averages about 17 days a month with a tenth of an inch of rain or more, which makes long dry stretches hard to find. January–February averages about 10 wet days a month, so wait for a clear stretch.
Best time to fertilize or treat a lawn in Hawaii
In Honolulu, the most reliable months are November–May. June–October can also work on the right days. June–October is hot, with highs near 88°F, so start early and keep out of full afternoon sun.
In Hilo, a typical month suits this job all year round.
How the weather differs across Hawaii
| Place | Hottest month avg high | Coldest month avg low | Rain per year | Last spring freeze | First fall freeze |
|---|---|---|---|---|---|
| Honolulu | 89°F | 67°F | 16 in | Rare | Rare |
| Hilo | 83°F | 64°F | 120 in | Rare | Rare |
Of the places above, Honolulu has the most good months for staining, painting and concrete combined (30 job-months), and Hilo has the fewest (2).
Monthly weather in Honolulu
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 81°F | 67°F | 3 | 1.8 in | 59% | 0 |
| February | 81°F | 67°F | 3 | 1.9 in | 58% | 0 |
| March | 81°F | 68°F | 3 | 2.4 in | 57% | 0 |
| April | 83°F | 70°F | 2 | 0.8 in | 55% | 0 |
| May | 85°F | 72°F | 2 | 0.8 in | 54% | 0 |
| June | 87°F | 74°F | 1 | 0.5 in | 52% | 0 |
| July | 88°F | 75°F | 1 | 0.5 in | 52% | 0 |
| August | 89°F | 76°F | 1 | 0.8 in | 52% | 0 |
| September | 88°F | 75°F | 2 | 0.9 in | 54% | 0 |
| October | 87°F | 74°F | 3 | 1.5 in | 57% | 0 |
| November | 84°F | 72°F | 3 | 2.3 in | 59% | 0 |
| December | 82°F | 69°F | 3 | 2.2 in | 60% | 0 |
*Days with 0.1 inch of rain or more; column notes.
Monthly weather in Hilo
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 79°F | 64°F | 10 | 7.9 in | 65% | 0 |
| February | 78°F | 64°F | 11 | 10.2 in | 64% | 0 |
| March | 79°F | 65°F | 15 | 12.7 in | 66% | 0 |
| April | 79°F | 66°F | 17 | 9.4 in | 67% | 0 |
| May | 81°F | 67°F | 14 | 7.0 in | 65% | 0 |
| June | 82°F | 69°F | 17 | 7.3 in | 65% | 0 |
| July | 83°F | 70°F | 19 | 9.2 in | 67% | 0 |
| August | 83°F | 70°F | 18 | 11.3 in | 67% | 0 |
| September | 83°F | 70°F | 15 | 8.7 in | 67% | 0 |
| October | 82°F | 69°F | 17 | 10.2 in | 69% | 0 |
| November | 80°F | 68°F | 17 | 14.4 in | 71% | 0 |
| December | 79°F | 66°F | 16 | 12.1 in | 69% | 0 |
Source: NOAA NCEI U.S. Climate Normals 1991–2020 for HONOLULU INTL AP, HILO INTL AP. See how the ratings work and how late in fall you can stain, paint or seal.
Frequently asked questions
When is the best time to stain a deck in Hawaii?
In Honolulu, October–June. In Hilo, no month is reliably good on average; pick dry spells carefully.
When is the last frost in Hawaii?
Honolulu almost never freezes; Hilo almost never freezes.
Can you pour concrete in winter in Hawaii?
Usually yes. Honolulu averages almost no freezing nights from December to February. Cover the slab if a rare freeze is forecast in the first 48 hours, and cure it as usual.
What months are best for sealing a driveway in Hawaii?
In Honolulu, every month of the year. In Hilo, conditions are marginal in most months, so choose warm, dry spells.