M.H.
We go to the pool almost every night (weather permitting). My kids are in daycare and they have a pool, and the other days they go to my moms for swim lessons.
Growing up, we were at the pool daily. My mom got us a family pass to the pool in town. That is where I went to swim lessons and now where my kids go.
We live in a condo, and the complex has a pool so it is easy for us to go often. And my MIL has a pool and she lives about 5 mins away..so we have access to many places.
So my kids swim 5 of 7 days if not more.
Summer is what you make of it.. Zoo, hiking, camping, fishing... what ever you do together is what they are going to remember. :)