There are very few restaurants here these days where you have to get "dressed for dinner". At the majority of establishments a clean short-sleeved shirt, a nice pair of dress shorts and "docksider" type shoes are sufficient. But you certainly won't be out of place in a nice pair of slacks and many of my male friends prefer them in the evening (as do I!).

It may get "chilly" at the beachside restaurants in the evening, especially in the winter. You may be more comfortable in long pants. And, if you've gotten any sun during the day, a light sweater or long sleeved shirt might be needed.

thanks for the replys