Most of California is exposed year round to surf that can range from one to fifteen feet in height. The size of the surf varies depending on the season of the year and the amount of exposure a beach has to the specific swell direction. Large surf is the primary cause of rip currents, long-shore currents, and beach erosion along the California coast.

Large surf is caused by swells, which are created by large storms blowing over the ocean surface. The size of the swell depends on the intensity of the wind within a storm, the amount of distance the wind blows across the water (called the fetch), and the amount of time the wind blows at a sustained speed.


During the months of May through September, swells generally approach California from the south and southwesterly direction. These swells are generated by storms in the South Pacific near New Zealand. South Pacific swells, also called Southern Hemisphere swells, travel thousands of miles across the ocean before breaking along the Southern California coast and can produce surf up to fifteen feet. These swells can be very unpredictable with long lull periods, making the ocean appear calm at one moment and then unleashing wave after wave the next.

South swells are also created by tropical storms and hurricanes off the coast of Mexico. These swells approach the Southern California coast at a more extreme south, southeast angle. These swells can also be unpredictable, extremely large, and powerful with waves that break one after another without any lull period in between.


During the months of October through April, swells generally approach California from the west and northwesterly directions. These swells are generated by storms that blow off Siberia and travel across the North Pacific Ocean on a west to east path. These storms reach their peak in the winter months and because of their closer proximity to the California coast, produce intense, and powerful waves up to fifteen feet at west and northwest facing beaches. Storm surge, strong currents, and cold water can accompany these swells as well as constantly changing bottom conditions. It is recommended that only properly equipped and experienced surfers with strong swimming skills enter the ocean during large winter swells.


Large surf can hold swimmers and surfers underwater for long periods, cause large currents and rip currents, throw swimmers and surfers into the bottom with enough force to injure bones and joints, and wash unsuspecting beach goers off jetties, rocks, and even a sandy shoreline