The Ergo is hot but one thing I do to help is loosen the straps so Liam is away from me a bit (he is 22 months old so a year older than yours) and it lets some air between us and that helps a lot. The hottest weather I have used it in is about 95 degrees, I will be using it when its over 100 too just because it gets that hot by noon when I pick up Hannah from school!