Best Time to Dive Oregon
Across 4 Oregon dive sites with multi-year conditions history, July historically shows the most favorable days — 93% of sampled days in the good band. The next-highest months are August (92%), May (78%) and September (76%). January historically shows the fewest favorable days (34% of sampled days). Average water temperature in the sample runs from about 10°C in March to 13°C in September. Typical seas range from 1.5 m to 3.2 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 Oregon?
| Month | Historically favorable days | Water temp | Typical seas |
|---|---|---|---|
| Jan | 34% | 11°C | 3.2 m |
| Feb | 38% | 10°C | 3.2 m |
| Mar | 41% | 10°C | 2.9 m |
| Apr | 51% | 11°C | 2.3 m |
| May | 78% | 11°C | 1.9 m |
| Jun | 74% | 11°C | 1.9 m |
| Jul | 93% | 11°C | 1.5 m |
| Aug | 92% | 13°C | 1.5 m |
| Sep | 76% | 13°C | 2.0 m |
| Oct | 58% | 12°C | 2.5 m |
| Nov | 39% | 12°C | 3.0 m |
| Dec | 34% | 12°C | 3.1 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 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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