It shouldn't be too hot in San Diego. They get cool beach breezes there. It's not hot like LA is!
I grew up in LA and we went to San Diego many times. We usually did day trips, so I don't have any hotel ideas. But there are three places are really huge, and almost need two days each to take it all in. Sea World, of course, and the Zoo is HUGE. We really like the San Diego Wild Animal Park, though. Come to think of it, though, the animals aren't real close, because they're allowed to live relatively as naturally as they can, in a savanna-like setting (giraffes, gazelles, buffalo, ostriches, zebras, rhinos all together in a huge pen) that you go see on a train.
You'll want to find a hotel very close so you can go back to it in the afternoon for naps, etc. Then you can go back to the parks after an early dinner. Take or rent strollers, and maybe take a baby backpack/carrier for the baby, just for a change of view. Take lots of snacks. That will help prevent meltdowns in the parks. Take sunscreen, of course.
You may also want to take a day to go to the beach. My 3 year old LOVED the beach when we went last year, and he still begs to go back. It's an opportunity you won't get too often in Logan!
You can check the weather forecast on www.noaa.gov before you go. You can also find some almanac information and see what the average temps are each month.
And since you have no one in school, you might consider going in early Fall. The weather will still be very nice, and you may get better deals on hotels, etc.
