Backdoor seasonal overview
Best Surf Season (October - March)
Backdoor sits squarely in the firing line of the North Pacific. As the Aleutian Low deepens in autumn, mid-latitude cyclones begin sending long-period ground swell toward the Hawaiian Islands, and Backdoor's northwest-facing reef suddenly lights up. Average swell heights climb from 2.0m (6.6ft) in October to 2.7m (8.9ft) in December and January, while average periods stretch from 10.7s to 12.8s. The swell rose during this window is loaded with energy from the NNW, NW, and N - exactly the directions that make Backdoor's shallow, barreling reef work. Trade winds still blow frequently from the ENE and E, but ideal offshore wind from the S through W quadrant arrives 21-27% of the time. When that wind window aligns with a solid NNW/NW ground swell, Backdoor is as good as it gets anywhere on earth.
Fair Surf Season (April, May & September)
The shoulder months are a mixed bag. April still carries an average swell height of 2.2m (7.2ft), but the period shortens to 10.3s and the direction mix tilts increasingly toward ENE and NE trade-wind swell. May drops further to 1.8m (5.9ft) and 9.2s, with the famous North Pacific ground swell becoming scarce. September is the mirror image: sizes are still modest at 1.7m (5.6ft), but the period lengthens back to 9.2s and the first pulses of NNW and N energy reappear. Onshore trade winds dominate much of the time, yet the occasional late April or early September north swell can still produce quality sessions at Backdoor. These months reward patience and a keen eye on the longer-range charts.
Low Surf Season (June - August)
The North Pacific storm tracks retreat during summer, and Backdoor falls into a deep seasonal lull. Average swell heights bottom out between 1.6m and 1.7m (5.2-5.6ft), with average periods of just 7.8-8.2s. The swell rose is almost exclusively short-period windswell from the ENE and E, generated by the strong trade-wind belt locked across the Pacific. Those same ENE/E trades blow onshore or cross-shore at Backdoor more than 90% of the time, and ideal offshore wind drops to a yearly low of just 9% in July. In short, the reef loses its draw, the ocean becomes bumpy and sectiony, and the famous barrels are nowhere to be found. Summer is for resting the quiver and waiting for the North Pacific to wake up again.