my son Ethan is a really snuggly baby. he was four months on wednesday and we still swaddle. i was worried about swaddling too, specifically that we were doing it for WAY too long but when he can sleep up to 9 hours swaddled and only a max of 5 unswaddled, it was a no brainer! Now i am slowly unswaddling, starting with one arm held up near his mouth to suck or leaving one arm unswaddled to avoid that jolting wake up as his arms fall to his crib. Sometimes he can unswaddle himself, in which case i leave him to sleep and try reswaddling in the crib when he moans (a bit of a success!).
as for heat, we spent part of the summer in Canada durring 30 + degree weather which Ethan was unused to (normal home = UK). we kept swaddling as he was in our room but left him in diaper only and more cuddly sheet.
just my experiences, good luck to you!