I’ve been to Oahu in all seasons and have witnessed what a dramatic difference Oahu’s North Shore is in Winter versus Summer. Winter months bring big waves to Oahu and turn the North Shore into a surfer’s dream. In summer months, the water is much more calm. Just see for yourself. We took the following photos of the beach at Turtle Bay Resort. Though the vantage points are different, I promise that these photos are of the same beach.
We snapped this photo in February 2009 from the shoreline.
(For even bigger waves just a few miles down the road and on the same day, take a look at my post on the Banzai Pipeline.)
We snapped this photo in June 2007 from the lanai at our room.
See this link for more examples of Hawaii in contrasts.