We did a 5 night (Cozumel and CC) out of Miami, Presidents week both 2014 and 2015. In 2014 it was beautiful warm weather the whole cruise, while 2015 was warm enough in Cozumel, but other days they were giving out blankets on deck. We also didn't make it to CC in 2015, but went to Nassau instead. We just stayed on the ship because it was so chilly and windy.
So, what I'm getting at is it can vary.