Bullfrog! It works like a charm and it is made specifically for kids. I used it on my oldest daughter when she was little because she was so fair-complexioned. She would burn at nothing. Her pediatrician's nurse actually told me about Bullfrog. I used it on her when we went to the lake and it did wonders so it went with us to the beach every time we drove down and she wore it at the pool and when playing in the yard here in the summer because it gets so hot.
Our summer temperatures can get up as high as the 100s with almost as high humidity so the kids, though now there is only our youngest, only go out in the summer until 11am and then they are inside until well after 4pm when it starts cooling down outside. I wrap our youngest in Bullfrog too even though she's darker than her sister (she has my complexion unlike her sister) but still with 100-degree heat, you can burn regardless of how dark-skinned one is. I use it if I'm going out too because lupus and Sjogren's disease not to mention almost every medication I take for it doesn't mix well with heat and especially when that heat is from natural sunlight.