Each year July to November, an ocean current pattern occurs that
effects the ocean’s surface currents in the Channel. During these months, the cooler northern pacific waters that dominate the overall California coast, and are called the California Current, slowly give way to a southern warmer current. As the gyre and counter current coming up from Mexico gain strength, more and more warmer waters are drawn up from the South and into the Channels – both San Pedro and Santa Barbara Channels.
By November, the main current effecting the Channel is now the
southern, warmer waters, which are part of the Davidson Current. As the year closes with the shortest days and longest nights, the waters right up to the shoreline are noticeably warmer and more inviting to human swimmers – as well as to the plant and animal life. It is ironic that when much of the rest of the Country is blanketed in snow and cold weather, the waters in the Channel are the warmest they will be each year.
Then February to March, and sometimes into June, the annual offshore
winds push strongly inland off the Pacific and cause the vertical upwelling that then interrupts the Davidson current, allowing the colder northern waters to once again reassert themselves in the Channel, and this causes the gyre to begin again by the summer months.
Each year these currents interact and transform the nature of the water
in the Channel, and influence life on he mainland and on the islands.