There are two North Shores, and which one you book decides what kind of holiday you have. This is not a matter of degree, like a rainy season being a bit wetter. It is a coast that faces directly into the North Pacific, and for roughly five months of the year the ocean along it is closed.
From about November to March, storms thousands of miles north send swell onto this shore in pulses that arrive over a day or two and last for several. Waimea Bay, Banzai Pipeline and Sunset Beach run at twenty to thirty feet and beyond on Hawaiian scale, which measures the back of the wave — so a twenty-foot day on the report is a face of around forty. Honolulu Ocean Safety closes beaches, flies red flags and pulls people out of water they should not have entered. The shorebreak at Waimea injures strong adults in water they can stand up in. Shark's Cove, which in August is the best shore snorkelling on this side of the island and shallow enough for children in the tide pools, is a place people are swept off the rock ledge in January. Several people die on this coast most winters, and a large share of them are visitors who did not know that the beach in the photograph is a different beach in February.
From about May to September, the same coast lies flat. Waimea Bay becomes a wide, calm swimming bay with the jumping rock in use. The reef at Pūpūkea and Three Tables goes clear. The water sits around eighty degrees, June and July are the two driest months of the year here, and the trades blow hard and steadily. This is the North Shore most visitors do not know exists, and if getting in the water is the point of your trip, it is the only correct answer.
The changeover is a forecast, not a date on a calendar. March routinely still takes winter swell. The first serious north swell often arrives in late October, and the character of the entire coast can change inside a week — snorkelling at Three Tables one day, lifeguards closing the beach the next. Any month given below is a probability, and the surf forecast for the day you are standing there overrides all of it.
What does not change much is the air. This is a mild coast: daytime highs run from around 79°F in the depths of winter to the mid-eighties in August, and overnight lows from the mid-sixties to the low seventies. Rain comes in short squalls rather than grey days, with December the wettest month at roughly two and a half inches and June and July comfortably under an inch. Nobody should cancel a North Shore day because of rain. They might well change it because of swell.
The rest of this page breaks it down month by month, separates the swimming answer from the surf-watching answer, and names the weeks that are genuinely quiet — which, on an island where most visitors stay in Waikīkī, are more numerous up here than you would expect.
