Hawaii records about 430mm of rain across roughly 100 wet days a year, which is a 27% chance on an average day. December is the wettest month at 62mm (14% of the annual total) and June the driest at 15mm. Local rain type: brief showers. Hawaiian rain is typically brief trade wind showers — they pass in 10-15 minutes. The leeward (west) side stays dry while the windward (east) side sees frequent rain. Rainbow-producing showers are a daily feature.
Chance of rain on an average day: 27%
Rainfall climatology for Hawaii. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Conditions on this page are recalculated from the latest forecast every time it is opened, for the current date in the location's own time zone. Showing .
| Annual rainfall | 430mm |
| Rain days per year | 100 |
| Odds on an average day | 27% |
| Wettest month | December — 62mm over 14 days |
| Driest month | June — 15mm over 3 days |
| Rain type | brief showers |
| Best dry window | May through September offers the driest weather with reliable sunset conditions on west-facing beaches. |
| Worst rain window | December and January bring Kona storms — rare southerly weather systems that can affect even the normally dry west side. |
December delivers 313% more rain than June (62mm vs 15mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 14% of the annual total, so rain in Hawaii is spread through the year — there is no season you can rely on being dry.
Hawaii rain typically comes as discrete showers, so a compact umbrella and a flexible plan are usually enough.
Rain falls on about 14 days in December against 3 in June — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 60mm | 13 | 43% | 27°C |
| February | 55mm | 12 | 40% | 27°C |
| March | 50mm | 11 | 37% | 28°C |
| April | 28mm | 6 | 20% | 28°C |
| May | 22mm | 5 | 17% | 30°C |
| June | 15mm | 3 | 10% | 30°C |
| July | 18mm | 4 | 13% | 31°C |
| August | 22mm | 5 | 17% | 31°C |
| September | 25mm | 6 | 20% | 30°C |
| October | 42mm | 9 | 30% | 30°C |
| November | 55mm | 12 | 40% | 28°C |
| December | 62mm | 14 | 47% | 28°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Hawaii we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Hawaii records rain on roughly 100 days a year — about a 27% chance on any given day — totalling around 430mm.
December, with about 62mm over 14 rain days. That is 14% of the entire year's rainfall in a single month.
June is the driest month at 15mm across roughly 3 days. May through September offers the driest weather with reliable sunset conditions on west-facing beaches.
Hawaiian rain is typically brief trade wind showers — they pass in 10-15 minutes. The leeward (west) side stays dry while the windward (east) side sees frequent rain. Rainbow-producing showers are a daily feature.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.