Persistence
A naive forecast: “it will stay as it is now”. Used as a reference: a useful model must do better.
Other terms
Bathymetry · Beach break · Breaking height · Confidence · Cross-shore wind · Crossed swells · Ensemble forecast · Forecast model · Gusts · Iribarren (breaker type) · Offshore wind · Onshore wind · Peak period · Period · Point break · Range · Reef · Rip currents · Seabed relief (EMODnet) · Set · Shorebreak · Submarine canyon · Swell · Swell direction · Tidal range · Tide · Tide coefficient · Wind sea