Don't know about cruise temps but my friend just flew back from the Mexican Riviera two weeks ago and she said the weather was wonderful! Sunny and warm. She packed shorts and if it's any reassurance....we live in the South and aren't accustomed to cold temps. We wear jackets when it gets below 60. So if she said it was warm...it was warm!
If you are going to walk on thin ice, you may as well dance!