What it means, wave heights, beach closures & how to stay safe
Note: Hawaiian wave heights are traditionally measured on the back of the wave (different from face height). A 10-foot Hawaiian wave looks much larger from the beach.
North Shore (Oʻahu, Maui, Kauai): Large swells arrive from October through April as North Pacific storms generate energy that travels thousands of miles. The Eddie Aikau big-wave contest at Waimea Bay requires 30-foot surf and has only been held a handful of times. November through February are typically the biggest months.
South Shore (All islands): South swells arrive from the Southern Ocean in summer, typically May through September. They are generally smaller than North Shore winter swells but can create dangerous conditions at usually-calm beaches like Waikiki and Ala Moana.
East Shore (Oʻahu, Maui): East and northeast swells can affect exposed beaches year-round but are most common in autumn. Sandy Beach, Makapuʻu, and Hana Bay can see dangerous conditions from these swells.
West Shore (Oʻahu): Makaha, Waianae, and surrounding beaches see large west swells particularly in winter. The Makaha International Surfing Championship is held here in big waves.
Check official sources first. National Weather Service (weather.gov/hfo) issues surf advisories. Check before leaving for the beach.
Choose a sheltered beach. When North Shore is under advisory, South Shore beaches are often calm. Ko Olina lagoons and east-facing coves may be protected depending on swell direction.
Watch the ocean before entering. Observe for at least 15 minutes. Identify rip currents, surge zones, and the wave pattern before going in.
Stay back from shoreline rocks. During high surf, waves can surge 20+ feet beyond the normal waterline onto lava rocks and sea cliffs. Keep a safe distance.
Respect beach closures. If a beach is closed by lifeguards or the county, it is closed for your safety. Fines apply for swimming in closed areas during high surf events.
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⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project not affiliated with the National Weather Service, Hawaii Emergency Management Agency, or any government agency. Surf advisory information is provided for general educational purposes only. Always check official NWS forecasts for current conditions.
For current surf advisories: weather.gov/hfo/surf
When in doubt, don't go out.