Waimea seasonal overview
Best Surf Season (October - March)
Waimea is a winter venue through and through. As the North Pacific storm track ramps up in October, the first serious NW and NNW groundswells of the season start lighting up the bay. By December and January the Aleutian Low is at its peak, flinging long-period swell trains across the Pacific toward Hawaii. Average heights climb to around 9ft (2.7m) with 12.8s periods in January, and the data shows NNW and NW directions supplying the majority of the open-ocean swell. These are powerful, pitching waves that hit the WNW-facing shore almost head-on. The saving grace is the trade-wind regime: E/ESE/SE flow blows offshore or side-offshore, keeping the faces relatively clean even when the bay is maxed out. This is the season when Waimea earns its reputation; from October through March you need respect, experience and the right board.
Fair Surf Season (April - May & September)
The shoulder months are a game of fading winter energy and rising summer trades. April still sees an average swell height near 7.2ft (2.2m) but the period drops to 10.3s and the energy source shifts from NW/NNW to NNE/NE/ENE. The waves become more wind-driven and less organized, though any late-season NW pulse can still produce clean, fun surf. September is the mirror image: the North Pacific is beginning to stir again, average periods climb back above 9s, and the first early NW swells of the season mix with the entrenched ENE trade windswell. Ideal offshore wind windows sit around 23-25% during these months, and with air temps in the low to mid 20s Celsius and water temps around 24-27°C, all you need is for a swell to align.
Low Surf Season (June - August)
Summer is Waimea's quiet period. The winter storm track retreats into the Gulf of Alaska and the North Pacific High dominates, so the bay defaults to short-period E/ENE trade windswell. Average heights sag to 5.2-5.6ft (1.6-1.7m) and average periods bottom out near 7.8-8.2s, with ENE directions contributing more than half of the swell distribution in June and July. The easterly trades are strong and consistent, which means waves are often clean but small and crumbly, lacking the power and size that define Waimea. It can still be fun for a groveler, but this is not the season for the famous bay.