June brings 30°C daytime highs, 15mm of precipitation across about 3 wet days and 13.3 hours of daylight — best for beach days, swimming and reliable sunshine. The strongest run of the year is June to August. December is the quietest month: quiet and local, and still good for green season and quiet and local.
Long-run climate normals for Oahu. Month ratings compare months within Oahu only — they are not a ranking of Oahu against other destinations, and they are not a forecast for a specific year.
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 .
| Best month | June — Beach days, Swimming, Reliable sunshine |
| Best 3-month window | June–August |
| Quietest month | December — Quiet and local |
| Driest month | June — 15mm |
| Wettest month | December — 68mm |
| Warmest / coolest | July 31°C / February 27°C |
| Seasonality | Fairly even across the year |
| Annual rainfall | 460mm over roughly 100 rain days |
December gets roughly 353% more precipitation than June — 68mm against 15mm. That difference, more than temperature, is what changes how a day here feels.
Daytime highs only move 4°C across the whole year (27–31°C), so timing matters far less here than rainfall does.
June gives you 13.3 hours of daylight against just 10.7 in December — a 3-hour difference in how much you can actually fit into a day.
June is the driest month at 15mm across roughly 3 wet days, while December peaks at 68mm.
July is almost as good as June, but usually quieter and cheaper. If your dates are flexible, it is the easier trip.
Oahu stays fairly consistent all year, so there is no month you need to avoid. What you plan to do matters more than when you go.
Ratings compare months within Oahu, not against destinations worldwide: five stars means the best time to be here, not that Oahu beats anywhere else. Tags describe what the conditions actually suit.
| Month | Rating | High / Low | Precipitation | Wet days | Sun | Daylight | Best for |
|---|---|---|---|---|---|---|---|
| January | ★★☆☆☆ | 27°C / 19°C | 65mm | 14 | 5h | 10.8h | Green season · Quiet and local |
| February | ★★☆☆☆ | 27°C / 19°C | 55mm | 12 | 3h | 11.3h | Quiet and local |
| March | ★★★☆☆ | 28°C / 19°C | 50mm | 10 | 3h | 11.9h | Quiet and local |
| April | ★★★★☆ | 28°C / 20°C | 30mm | 6 | 6h | 12.5h | Beach days · Swimming |
| May | ★★★★☆ | 30°C / 21°C | 25mm | 5 | 6h | 13h | Beach days · Swimming |
| June | ★★★★★ | 30°C / 22°C | 15mm | 3 | 11h | 13.3h | Beach days · Swimming · Reliable sunshine |
| July | ★★★★★ | 31°C / 22°C | 18mm | 4 | 11h | 13.2h | Beach days · Swimming · Reliable sunshine |
| August | ★★★★★ | 31°C / 22°C | 20mm | 4 | 11h | 12.7h | Beach days · Swimming · Reliable sunshine |
| September | ★★★★☆ | 30°C / 22°C | 28mm | 6 | 11h | 12.1h | Beach days · Swimming · Reliable sunshine |
| October | ★★★☆☆ | 30°C / 21°C | 45mm | 9 | 6h | 11.5h | Beach days · Swimming |
| November | ★★☆☆☆ | 28°C / 20°C | 58mm | 12 | 6h | 11h | Beach days · Swimming · Quiet and local |
| December | ★★☆☆☆ | 28°C / 19°C | 68mm | 14 | 3h | 10.7h | Green season · Quiet and local |
| You are planning | Pick | Why |
|---|---|---|
| Sun & beach days | June | 11h daily sunshine, 30°C highs and only 3 rain days. |
| City walking & sightseeing | June | 30°C highs with 13.3h of daylight — long days without heat fatigue. |
| Photography & light | June | 11h of sun and 13.3h daylight give the widest window for golden-hour work. |
| Value & fewer crowds | September | Scores 75/100 — close to peak conditions but outside the busiest window. |
| Cooler-weather travel | April | 28°C highs and 20°C nights suit anyone who dislikes heat. |
Each month in Oahu is described from long-run climate normals and then rated relative to the other eleven months in the same city. A five-star January in a cold destination means January is one of the best times to be there — not that it beats a Mediterranean summer.
| Factor | Weight | What it measures |
|---|---|---|
| Temperature | Described | Average daytime high and overnight low for the month, shown as measured rather than judged. |
| Precipitation | Described | Monthly millimetres and wet-day count, labelled as snow or rain/snow where temperatures make that the likely phase. |
| Sunshine & daylight | Described | Average daily sunshine hours and astronomical daylight length at mid-month, from the city’s latitude. |
| “Best for” tags | Derived | Applied only when the conditions genuinely support the activity — snow depth-friendly cold for skiing, 13–24°C and low rain risk for hiking, dark evenings at high latitude for aurora. A month with few strong use cases gets fewer tags rather than padded ones. |
| Star rating | Relative | Ranks the month against the other eleven months in the same city. Never a comparison between cities. |
Figures are long-run climate averages, not a forecast for a specific year. Where a month lacks sourced rainfall or humidity, the value is modelled from temperature range and rain frequency.
June is the best all-round month in Oahu: 30°C highs, 15mm of precipitation and 13.3 hours of daylight, which suits beach days, swimming and reliable sunshine. The strongest three-month window is June to August.
December — 28°C highs, 68mm of precipitation over roughly 14 days and 10.7 hours of daylight. It is the cheapest and least crowded time to go, and it still works for green season and quiet and local.
June is the driest month at 15mm over about 3 rain days, against 68mm in December. Across the year Oahu records around 460mm.
Yes — conditions in Oahu stay fairly even all year, so there is no month you need to avoid. What you plan to do matters more than when you go.
Daylight ranges from 10.7 hours in December to 13.3 hours in June, calculated from the city's latitude.