If San Diego is soggier than a sea slug and your vacation plans need a rain check, here's the first thing to do. Walk around humming the Peabo Bryson song "Can You Stop the Rain" and singing to everyone you meet that you thought it "never rains in Southern California."
If your day is still taking on water after that, you could poke out your lower lip in a sulky pout, but it's unlikely to stop the precipitation. A better plan would be to find something to do indoors. Try the San Diego Museum Guide or browse the list of indoor day trips.
A rainy day is the only time you won't look silly wearing a pair of galoshes in San Diego. Dress comfy and if you have some rain gear, you also have more options.
Try these ways to outfox the raindrops.
Good Places to Go on a Rainy Day
You might think of Las Vegas rather than San Diego when someone mentions gambling, but you'll find plenty of Casinos within driving distance of San Diego.
In La Jolla, the Birch Aquarium is a good place to spend some time. We especially like their seahorse exhibits.
The athletes may be training to make their push for the gold outdoors, but you can go inside to see how they do it at the Chula Vista Olympic Training Center.
How 'Bout a Cuppa?
San Diego has several places to enjoy an afternoon tea, an especially nice thing to do on a rainy day. Tea Upon Chatsworth is a well-rated, relaxing and elegant place to enjoy it.
Go Play Inside
If you can't play outdoors, go to a place that brings outdoor activities inside.
Miramar Speed Circuit takes go-kart racing indoors, but doesn't slow them down. Those little karts can go up to 40 miles per hour.
The Old Standbys
More About San Diego on a Rainy Day
In San Diego, it's more likely to rain pygmy shrews and teacup Chihuahuas than cats and dogs. Even though it's raining, all you may need is a hat or a bumbershoot.
Locals may enjoy rain because it's something different than their usual weather, but if the local driver's license test included how to drive in it, not a single person would ever pass. Watch out for them because they may not watch out for you.
In general terms, the rainy season runs from November through March. For average highs, lows sunshine and rain, check the San Diego weather guide.