Coastal Science
Two Feet of Water: What King Tides Actually Do to San Diego Beaches
· 5 min read
A king tide is not a storm. It is about two extra feet of ocean — and on a coast this narrow, two feet is the difference between a beach day and water in a doorway.
No storm. No swell. No wind.
Just the ocean, arriving about two feet higher than it usually does, and a walkway in Mission Beach that turns into a canal for ninety minutes.
That is a king tide. It is the least dramatic disaster San Diego has, and the one most likely to reshape the coast you actually use.
Interactive stat band — view the live version on this page.
Two feet. That is the whole story.
Interactive tide scale — view the live version on this page.
Two feet sounds like nothing. Put it on a beach that has been quietly narrowing for fifty years and it stops sounding like nothing.
On a wide beach, two feet moves the waterline a few steps up the sand. On a narrow one, it moves the waterline into the seawall, the bluff toe, the parking curb, the alley.
San Diego has a lot of narrow beaches now.
What it looks like, beach by beach
Interactive status strip — view the live version on this page.
Five things to do with this
- Check the number, not the weather. A calm blue afternoon at 7 ft floods things a gray day at 5 ft never will.
- Arrive on the outgoing tide. Two hours after peak, you get back the beach you came for.
- Park uphill in Mission Beach and Imperial Beach. Curb-height water finds tires first.
- Stay off the bluff toe entirely at peak. No dry sand means no exit if a set stacks up.
- Flip it: the low tide that follows is enormous. King tide cycles produce the year's best tidepooling within hours of the worst flooding.
The part that is genuinely new
King tides are old news — sun, moon, gravity, entirely predictable, centuries of them.
What changed is the floor they start from. Southern California's water level used to rise about 2 mm a year. It is now running 3 to 4 mm a year. The tide is not getting stronger. The baseline is getting higher.
Which means the tide that just barely reached the walkway this year is the tide that goes past it next year, with the same moon and the same calm sky.
Interactive next tide — view the live version on this page.
Bottom line
You do not need to be alarmed by king tides. You need to be scheduled around them.
Two feet is not a catastrophe. Two feet on a beach with nothing left to give is how a beach disappears — slowly, on beautiful days, while nobody is filming.
