Tides — the water’s own schedule
Tides move more water than any wind does, and on many sites they decide the current, the entry and the visibility. Boats plan around them; shore divers should too.
The gentlest water is around the turn of the tide — 'slack' — when the flow pauses before reversing. On current-swept sites, dives are timed to it; miss the window and the same site can be undiveable. High-water slack usually also brings the cleaner, bluer water in from the sea.
Around full and new moon ('spring' tides) the range is biggest: stronger currents, more stirred-up sand, shorter slack. Around the quarter moons ('neaps') everything is gentler. If a site is marginal for you, a neap week is the kinder booking.
A rocky platform you strode off at high water can be an urchin-covered scramble two hours later — check the height for your exit time, not just your entry. On lagoon and bay sites an ebbing tide can also drain milky, stirred water out over the reef.
The Med's tidal range is small (often under 40 cm), so around Cyprus, Greece or Malta wind and swell matter far more than tide. In the Red Sea, the Atlantic, the North Sea or Southeast Asia, the tide table is part of the dive plan.
Check the forecast
Free 7-day tide tables for thousands of coastal locations worldwide.
The weather map many divers already use; picking a coastal spot shows nearby tide stations in the detail panel.
The authority for US waters — predictions straight from the measuring stations.
Tide predictions are external services’ own — and your dive centre times current-dependent sites daily; when their briefing and a website disagree, the briefing wins. See also wind & waves.