We went to a Braves night spring training game two years ago, and I agree about the temp drop - we were glad we wore jeans. We enjoyed the game a lot. If you are planning to go to a game, I'd advise you to go online and order your tickets ahead of time. We did that, and were glad we did because the game was sold out. I'm not sure if that game was an exception - maybe they all aren't sold out - but that was our experience. We were able to pick up our tickets at the will-call window, and by ordering ahead of time, we were able to get decent seats.
We'll be down there again in March, and are planning to go see the Red Sox play Cleveland at Winter Haven. If you are a big baseball fan, you can't beat Spring Training, because you are just so much closer to the players than you can usually get during the regular season.
Enjoy!
Tigger22