I've been taking my LO to the water parks since she was 9 months and she's always LOVED them! At 15 months I'd choose Blizzard Beach over Typhoon because the kiddie area is better for that age than Typhoon's and the wave pool is a lot milder. Both have lazy rivers so that isn't an issue. There was plenty for my daughter to do and she enjoyed it enough at 15 months that we could stay for hours. It is best to either get there right at opening and stay until they are worn out or go around 2-3:00 and stay until closing because mid-day is a lot more crowded. Obviously one adult will have to stay in the kiddie area most of the time so we trade off. We actually just went to Blizzard Beach a few weeks ago with my 15 month old nephew, my 3 1/2 yr old daughter and my 3 1/2 yr old nephew. All of them loved it & lasted from opening until 3:00. The 15 month old did not enjoy the family raft ride but the 3 1/2 yr olds loved that, the lazy river, the wave pool, the kiddie area, and everything we let them do in the preteen area (my daughter at 3 1/2 is a very strong swimmer but my 3 1/2 yr old nephew can't swim at all).