Breastfeeding mommas need some advice

I've been thinking a lot lately about when I'm in public with my son and he needs to eat. He's due in 3 days and with it starting to get really warm outside I'm not going to want me an baby under a hot blanket if we're outside, I go to my nephews baseball games for example and I just don't know how to go about breastfeeding him without all the problems in a situation like that. Any stories or words of encouragement would be greatly appreciated.