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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. The next-highest months are January (99%), October (99%) and November (99%). December historically shows the fewest favorable days (97% of sampled days). Average water temperature in the sample runs from about 8°C in February to 14°C in August. Typical seas range from 0.1 m to 0.3 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 Washington?

MonthHistorically favorable daysWater tempTypical seas
Jan99%8°C0.2 m
Feb99%8°C0.2 m
Mar100%8°C0.2 m
Apr100%9°C0.2 m
May100%11°C0.2 m
Jun100%12°C0.2 m
Jul100%14°C0.1 m
Aug100%14°C0.1 m
Sep100%13°C0.1 m
Oct99%11°C0.2 m
Nov99%10°C0.2 m
Dec97%9°C0.3 m

% = share of sampled days scoring in the favorable band, median across 11 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.

Bars are Jan–Dec — months when sightings historically concentrate (GBIF occurrence records). Wildlife is never guaranteed.

Diving Washington soon? Browse its dive sites with auto-updating 7-day condition windows — free, no account needed.

Choosing between destinations? Compare them month by month with the Trip PlannerPro