Best Time to Dive Washington
Across 11 Washington dive sites with multi-year conditions history, March, April, May, June, July, August and September historically show the most favorable days — 100% of sampled days in the good band.
Computed from our own conditions climatology — measured history, not brochure copy. Historical patterns, never a forecast or a guarantee.
Month by month
| Month | Historically favorable days | Water temp | Typical seas |
|---|---|---|---|
| Jan | 99% | 8°C | 0.2 m |
| Feb | 99% | 8°C | 0.2 m |
| Mar | 100% | 8°C | 0.2 m |
| Apr | 100% | 9°C | 0.2 m |
| May | 100% | 11°C | 0.2 m |
| Jun | 100% | 12°C | 0.2 m |
| Jul | 100% | 14°C | 0.1 m |
| Aug | 100% | 14°C | 0.1 m |
| Sep | 100% | 13°C | 0.1 m |
| Oct | 99% | 11°C | 0.2 m |
| Nov | 99% | 10°C | 0.2 m |
| Dec | 97% | 9°C | 0.3 m |
% = share of sampled days scoring in the favorable band, median across 11 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 California & Pacific Northwest region — not site-specific promises.
- Great white sharkAug–Nov
- Ocean sunfishJul–Dec
- Thresher sharksJul–Dec
- OrcaMar–Oct
- Humpback whaleyear-round
Bars are Jan–Dec — months when sightings historically concentrate (GBIF occurrence records). Wildlife is never guaranteed.
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