Every diver has lost money to the wrong month. Booking a liveaboard three weeks before the thermocline drops, or chasing mantas in a channel they vacated in April. Dive travel advice is full of destination reviews and gear guides. Finding a reliable answer to "is this the right month to go?" is surprisingly hard.
Most resources treat timing as an afterthought — a paragraph at the end of a destination guide that says "best visited October through May." WhenToDive is an attempt to flip that: a structured, month-by-month reference that makes the calendar the primary axis, not a footnote.
Every destination is scored 1–5 for each month of the year, based on operator season guides, published liveaboard schedules, and Wikipedia climate data. The scores are a holistic judgement of dive quality — visibility, sea conditions, species activity, and seasonal events — deliberately simple enough to use without a legend. The search tool and comparison tool let you slice that data by month, species, region, skill level, or budget.
This is the reference we wished existed.