Best Time to Dive Hawaii - Oahu
Across 4 Hawaii - Oahu dive sites with multi-year conditions history, July historically shows the most favorable days — 99% of sampled days in the good band. The next-highest months are June (99%), September (99%) and August (92%). January historically shows the fewest favorable days (16% of sampled days). Average water temperature in the sample runs from about 25°C in February to 27°C in October. Typical seas range from 1.3 m to 2.3 m of significant wave height through the year. These figures are historical climatology computed from measured conditions — patterns, not a forecast or a guarantee.
Computed from our own conditions climatology — measured history, not brochure copy.
Which months are historically most favorable in Hawaii - Oahu?
| Month | Historically favorable days | Water temp | Typical seas |
|---|---|---|---|
| Jan | 16% | 25°C | 2.3 m |
| Feb | 40% | 25°C | 2.0 m |
| Mar | 66% | 25°C | 1.8 m |
| Apr | 77% | 25°C | 1.7 m |
| May | 89% | 26°C | 1.5 m |
| Jun | 99% | 26°C | 1.3 m |
| Jul | 99% | 27°C | 1.3 m |
| Aug | 92% | 27°C | 1.3 m |
| Sep | 99% | 27°C | 1.3 m |
| Oct | 78% | 27°C | 1.6 m |
| Nov | 57% | 26°C | 1.9 m |
| Dec | 30% | 26°C | 2.1 m |
% = share of sampled days scoring in the favorable band, median across 4 dive sites with at least two years of history. Ringed = historical peak.
How does this compare worldwide? The Most Reliable Diving Months on Earth ranks 61 countries by the same measure.
Marine life seasons
Sighting patterns across the wider Hawaiʻi region — not site-specific promises.
- Green sea turtleDec–Feb
- Reef manta rayJune
- Humpback whaleDec–Apr
Bars are Jan–Dec — months when sightings historically concentrate (GBIF occurrence records). Wildlife is never guaranteed.
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