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.
Frost dates matter for concrete, which must not freeze in its first 48 hours, for paint and caulk that need nights above their minimum, and for lawn care, since crabgrass preventer goes down as the soil warms in spring. See how late in fall you can stain, paint or seal.
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. 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.
Check this week’s hour-by-hour verdict with the deck staining forecast.
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. 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.
Check this week’s hour-by-hour verdict with the exterior painting forecast.
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.
Check this week’s hour-by-hour verdict with the concrete pouring forecast.
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.
Check this week’s hour-by-hour verdict with the driveway sealing forecast.
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.
Check this week’s hour-by-hour verdict with the lawn fertilizer forecast.
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). If you live between them, expect something in between, and higher ground to be cooler with a shorter season.
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 at least 0.1 inch of rain or melted snow. Freezing nights: average nights a month at or below 32°F. Humidity is calculated from NOAA hourly normal temperature and dew point at 3 PM.
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 |
Use the averages, then check the forecast
These ratings describe a typical month, not a particular week. A warm spell in a “poor” month can give you a good day, and a wet week can spoil a “good” one. Use this page to plan the season, then check the 7-day forecast for your ZIP code before you buy materials or book help. Each project forecast checks the hours after you finish too: overnight lows, dew and rain that would ruin fresh stain, paint, sealer or concrete.
About this data
Monthly temperatures, rain days, snowfall and freeze dates are NOAA National Centers for Environmental Information (NCEI) U.S. Climate Normals for 1991–2020 at HONOLULU INTL AP, HILO INTL AP. Ratings apply the same temperature limits as our forecasts (for example, 50°F or warmer for deck stain and driveway sealer, and no freezing nights for new concrete) to the average month. Your product label always takes priority.
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. Look for at least 24 dry hours before and after, and nights above about 40°F. The deck staining forecast checks your exact week.
When is the last frost in Hawaii?
Honolulu almost never freezes; Hilo almost never freezes. These are median dates from NOAA 1991–2020 normals, so a freeze after them happens in about half of years. Low spots and valleys freeze later in spring.
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. Most sealers need 50°F or warmer for 24 hours and a dry day after. See the driveway sealing forecast.