During Hawai‘i’s winter, October-April, and sometimes into spring, storms in the North Pacific create very large, open ocean swells that track toward the equator, passing by the state and expending the wave energy on the reefs and beaches. This is great news for surfers, who follow these swells closely and live to surf the powerful waves, which can break up to 60 feet on the face during the biggest surges on the outermost reefs. For snorkelers and divers, high surf is a worst-case scenario.
Once summer rolls around, the tables turn. From May to September, the North Shore becomes a tranquil swimmer’s paradise. The waves usually remain flat the entire period, the sand settles, and the water becomes crystal clear. Snorkelers and divers revel in the conditions, and the focus on the North Shore shifts from the waves above the surface to the exploration of its underwater world.
Excerpted from the Seventh Edition of Moon O’ahu.