Waimea Bay Alert Guide

Hawaii, USA · part of the Waimea Bay spot guide

The Waimea buoy sits about six kilometres off the bay and is the definitive reference gauge for the entire North Shore, so a live-observation alert is exactly right here — when 51201 actually reads a giant long-period swell from the northwest, the Bay is breaking. Because it only breaks big, the height threshold below is deliberately high.

The forecaster's checklist

1. 1.Find an intense North Pacific / Aleutian low with a long fetch aimed at Hawaii from around 300–340°.
2. 2.Use the buoy relay: long-period forerunners show on the offshore buoys (51001, 51101) roughly 8 to 15 hours before they reach 51201 at Waimea.
3. 3.Apply the roughly two-times Hawaiian-to-face factor, and weight period as much as height — a long-period swell fills the bay where a short one won’t.
4. 4.Read the thresholds off 51201: the bay turns on around 15 ft of significant height at long period, works up to about 40-foot faces, and closes out past roughly 22 ft.
5. 5.For an Eddie-scale day, look for sustained 20-foot Hawaiian swell — a touchstone of about 20 ft at 20 seconds on the buoy that holds rather than spikes.

Local winds & tide

Best wind: NE–ENE trades blow side-offshore; cleanest on E–ESE offshore — from 45° to 120° (NE–ESE).

The tidal range here is small, so tide is a secondary modifier — swell size and period dominate the call entirely.

Dial it in