A few summers ago, we did a 4 day baja on RCCL. It was during june or july. Anyways, during the day it was hot. But, once the sun went down it was cold to very cold. So cold, we spent $60 each on a sweatshirt/hoodie in the gift store on the boat. We didn't even think to bring any jackets, it was the middle of summer. Enjoy and Bon Voyage.