Why California's Beaches are Cold

California's Chilly Waters are due to Ocean Currents and Upwelling

Apr 7, 2009 Megan Jungwi

California's beaches are cold and with reason! California's cold waters can be explained with a little knowledge of how ocean waters move through currents and upwelling.

Sunny California has very cold beaches. Anyone who’s taken a dip out of Los Angeles, San Francisco, or San Diego will know that California’s waters are not the most fun for swimming in. Indeed, the surface temperature of California’s ocean often hovers around 60 degrees Fahrenheit. Although one might wish for warmer water, California’s beaches are destined for chilliness because of the way ocean currents and upwelling work.

Ocean Currents Make for Chilly California Beaches

The ocean contains many different currents. Some are small and constantly changing, some extend over large swaths of the ocean and are relatively stable. An example of the latter is the North Pacific Gyre which is comprised of several currents moving water around the northern Pacific Ocean. The Gyre travels in a clockwise circular pattern moving water west across the equator, north up the coast of Asia, east below Alaska, and runs south along the California coast. This is the first reason California has cold water. The portion running south along the California coast is called the California Current. This current brings cold Alaskan waters down to California, waters which won’t warm up again until they’ve traveled along the equator.

Upwelling Brings Cold Water Up From Below

California’s beaches have cold water coming from the north, but they also have cold water coming from its own depths. Water at the surface gets more sunlight than water deeper down. Thus, water is warmer at the surface and colder at depth. Upwelling is the movement of deep cold waters coming to the top and is caused by wind. When wind blows parallel to a coastline, as it does off the California coast, it can move water at a right angle to the direction the wind is blowing. This movement is aided by the Coriolis effect. So, as water at the surface is being pushed away from the coast, water is drawn from below to replace it. That is, cold chilly water coming to the surface.

Why Cold California Water is Good For You

Although the cold water may not be the ideal for a swimmer in his bathing trunks, the currents and upwelling are important to many marine creatures. Upwelling in particular is important in bringing nutrient-rich water up to the surface forming the base of an important food chain. Phytoplankton feeds on these nutrients and many fish, marine mammals, and seabirds feed on the phytoplankton. This creates a productive fishery and good eating. The U.S. National Oceanic and Atmospheric Administration (NOAA) reports that coastal upwelling regions account for only one percent of the ocean’s surface but make up fifty percent of the world’s fisheries.

So, while many a boy and girl is deterred from swimming in California, at least everybody gets to eat.

References

Gaines, Steve and Satie Aramie. “Upwelling”. NOAA Ocean Explorer. 11 July 2005. Retrieved on 7 April 2009. URL: http://oceanexplorer.noaa.gov/explorations/02quest/background/upwelling/upwelling.html.

Gardiner, Lisa and Becca Hatheway. “Surface Ocean Currents”. Windows to the Universe. 31 September 2008. Retrieved on 7 April 2009. URL: http://www.windows.ucar.edu/tour/link=/earth/Water/ocean_currents.html.

The copyright of the article Why California's Beaches are Cold in Marine Biology & Oceanography is owned by Megan Jungwi. Permission to republish Why California's Beaches are Cold in print or online must be granted by the author in writing.

A California Beach

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