Napa or San Diego?

Napa swaps the sea for the pool. Hot, dry summer afternoons there are spent beside a resort pool between tastings. The Sonoma coast is a long drive away, and its cold Pacific is for looking at rather than swimming in.

San Diego lives along its shoreline. The boardwalk at Mission and Pacific Beach is full of surfers, cyclists and volleyball players, while Del Mar, Encinitas and Carlsbad have quieter beaches below the cliffs. With a wetsuit you can surf all year, and the only question on a beach day is which stretch of sand to choose.

At the Oxbow Public Market you can work through oysters, cheese, charcuterie and fresh bread under one roof, and that sums up how Napa eats: the food grows out of the wine and the farms around it. Family cellars in the side valleys pour Cabernet, Carneros adds Pinot Noir and sparkling wine, and a short drive up the valley brings you to some of the most celebrated restaurants in the country. For a trip planned around meals, Napa has the stronger table, although cheap eating mostly means the taquerias.

San Diego's food is looser and more varied. Baja fish tacos, late-night taco shops and California burritos stuffed with fries all come from the border, North Park and Miramar pour hop-heavy West Coast IPAs, and Convoy Street is lined with Korean, Japanese and Vietnamese kitchens. That fills the cheap, varied gap Napa leaves, but nothing here matches the valley's best restaurants.

San Diego has far more to see. Balboa Park's Spanish Colonial Revival buildings hold the art, natural history and air and space museums, the USS Midway is moored on the waterfront, and Old Town, the first California mission and Cabrillo National Monument tell the region's early story.

Napa has a few Victorian streets, the restored 1880 Opera House, the contemporary art at di Rosa and the old stone wineries up the valley. That fills a day at most, so anyone who likes museums will be happier in San Diego.

Napa's evenings end with dinner and perhaps one more glass at a downtown wine bar, and the valley is quiet by late evening. For anything livelier you have to go to San Francisco.

San Diego offers a real choice. The Gaslamp Quarter has rooftop bars and dance clubs, Pacific Beach is a rowdy student and surfer strip, and Hillcrest and North Park are better for cocktail bars, brewery taprooms and the city's gay scene. It is not a party destination, but you can go out every night of a stay.

Napa's outdoors is gentle and pastoral. You can float over the vineyards in a balloon at dawn, cycle the flat valley trail, walk among the redwoods at Bothe-Napa Valley or climb Mount St Helena for the views, with Point Reyes and Muir Woods within a long day's reach.

San Diego has more range and can be enjoyed all year. There are sea lions at La Jolla Cove, sea caves to kayak into, Torrey Pines trails above the ocean, tide pools and whales passing in winter. About an hour inland are pine-covered mountains and the Anza-Borrego desert.

Napa is the better base for outings. Sonoma's plaza and mission are about half an hour away, Healdsburg and the Russian River valleys make a second wine region to explore, and San Francisco is about an hour away by car or by ferry from Vallejo. Sacramento is not much further.

San Diego's list is more unusual than rich. Tijuana is a trolley ride and a walk across the border, and Mexico's Valle de Guadalupe wine region, Temecula and the apple-pie town of Julian all make good drives. Los Angeles, though, is a longer and less predictable trip than San Francisco is from Napa.

This is where the two differ most. San Diego is one of the easiest cities anywhere to bring children to: the zoo in Balboa Park, the Safari Park, SeaWorld, Legoland, the Birch Aquarium and calm paddling at Mission Bay, all in weather that rarely lets you down.

Napa is made for adults. Tasting rooms bore children, the drives between wineries are long and summer afternoons are hot. The animal park in Vallejo, the geyser near Calistoga and the hotel pools help, but they will not fill a week.

Both cities have walkable centres and need a car beyond them, but San Diego has more alternatives. The trolley links downtown, Old Town and the border, and coastal trains reach the North County beach towns, although La Jolla and the big attractions still mean driving.

In Napa, the riverfront and the market hall are close together, but the wineries are spread along some 50km of valley road with almost no useful buses. Because tasting and driving do not mix, most visitors pay for a driver or join a tour.

The two are close here, with San Diego a little broader, and they differ mainly in what you take home. In Napa it is wine, often cases shipped from the cellars you visited, plus olive oil and food gifts from the Oxbow Public Market and cookware along St Helena's main street.

San Diego adds the luxury brands at Fashion Valley, vintage and design shops in North Park and Little Italy, galleries in La Jolla, and Mexican crafts and pottery in Old Town.

Neither city is cheap, but Napa costs more. Luxury resort rooms, paid tastings at the famous estates, special-occasion dinners and a hired driver all add up quickly, and even the thrifty options of chain hotels and taquerias leave it an expensive trip.

San Diego is easier on the wallet. The beaches and the gardens of Balboa Park are free and the taco shops are cheap. Families should allow for the steep admission at the zoo and theme parks, though, along with parking for a hire car.

San Diego has a real theatre scene. The Old Globe's open-air Shakespeare stage in Balboa Park and the La Jolla Playhouse both produce shows that have gone on to Broadway, and the symphony plays a summer season on the bay.

Napa has more than its size suggests: concerts and comedy at the old Opera House, touring bands at an Art Deco theatre, a summer classical festival at the wineries and a big rock festival at the fairgrounds in late spring. Outside those moments the programme is thin.

Napa is the better place to unwind properly. Calistoga has been a hot spring town since the nineteenth century, and its volcanic mud baths and mineral pools are the classic end to a day of tastings. The resorts in Carneros and the hills add large spas, and the whole valley moves at an unhurried pace.

San Diego relaxes you in a different way. There is no bathing tradition, but there are resort spas in La Jolla and Coronado, yoga in Encinitas, and sunset walks along the shore.