Engagement Photos: When?

My wedding is in September 2005 and our photgrapher includes an engagement photo shoot.

We want to take the pics down at the beach, I am wondering when we should have them taken?

Any ideas? I think it would be way too cold to go down and do it now, but I also worry that because I live out of state and would need to get them taken on a weekend, I should plan something soon before the busy wedding season starts up again....

Thoughts?