Expect highs around 80 and lows around 60. Whether that requires a jacket depends on how hot or cold natured a person is. At those temps, my wife will need a jacket at night and at the restaurants. I will not. We only buy cars that have duel temperature zones.
If you're further up north, I would pack a swim suit. I live outside of Memphis. The weather has been cool for this time of year. It hit 80 yesterday and I was sweating. Disney pools are heated. I believe they are supposed to be at 82 degrees.