SAN DIEGO -- San Diego tourism is being hit hard in June, according to experts.

After a strong Memorial Day weekend, hotel occupancy is down.

Tourism is San Diego's third-largest industry, behind the Navy and manufacturing.

Experts said tourism is struggling in many tourist destinations, but the Convention and Visitors Bureau has a plan to get more people to come to San Diego and dump more money into the local economy.

The Curtis family is visiting San Diego this week from Phoenix.

"It's 110 degrees at home. It seemed like a good time to get out," said Rob Curtis.

Experts said San Diego is in need of more visitors like the Curtis family, as it has been a tough month for local hotels.

One week earlier in June, hotel occupancy in San Diego was down 43 percent from the same week last year. Part of that was fewer groups were in town, and part of it was the "June gloom" and fears of swine flu.

"Swine flu had a major effect. Fortunately, we've seen that somewhat dissipate," said Joe Terzi of the Convention and Visitors Bureau (ConVis).

Terzi said the summer push is on and they've spent $10 million on ads to be aired on national cable and West Coast markets.

"The pre numbers for July 4 are very strong. We actually are seeing some very strong occupancies going toward the summer," said Terzi.

ConVis is not selling specific attractions in San Diego but a feeling, with one TV ad -- called "Happy Happy" -- that sums up the approach.

"The people in the focus groups told us, 'When I come to San Diego I feel good. I feel happy.' And that's really where that came from," said Terzi.

At Seaport Village, Ben Abdeljalil is not so happy because his Island Hoppers store gets 60 percent of its business from tourists and conventions.

"Could be better, but we have suffered a little bit the last few months. Hopefully this summer it will catch up," said Abdeljalil.

ConVis hopes July and August tourism will be about the same as last year and that people who come to San Diego will enjoy what they find and spend some money.

One research firm estimates San Diego hotel revenues will drop 24 percent this year.

Terzi said that is close mostly because hotel rates are down as hotels offer more and more deals.