The North Shore runs on two entirely different schedules depending on the season. Winter (November through February) is surfing season: the northwest swells arrive, the professional circuits run their competitions at Pipeline, Sunset, and Waimea, and the beaches are lined with spectators watching some of the largest waves in the world break close to shore. Swimming is dangerous to impossible at most North Shore beaches during this period, but the spectacle is extraordinary.
Summer (May through September) transforms the coastline. The same beaches become calm, clear, and excellent for swimming and snorkeling. Shark's Cove in Pupukea has some of the best reef snorkeling on Oahu when conditions are right. The crowds shift from surfers and surf spectators to families and snorkelers. Prices and visitor numbers at Haleiwa town peak in summer. Spring and fall are transitional and can produce the best combination of conditions: manageable waves for intermediate surfers, good swimming, and fewer visitors.