El Nino Watch
Forecast maximum wave height off Samui, today and the next 2 days.
Koh Samui watch
Daily maximum significant wave height from the Open-Meteo marine model, for open water east of the island.
Limits. A model value for one grid point; the Donsak ferries cross the more sheltered southwest side, the Chumphon catamaran the open Gulf. Operators decide cancellations themselves.
Below 2 m: ok. 2 to 3 m: caution (catamarans and small boats are cancelled first). 3 m or more: blocked (car ferries likely suspended). No recent forecast: unknown.
The ferries to Donsak and the catamarans to Chumphon are the main way off the island.