Hardening off plants but they are dieing...?

I've been trying to harden off my broccoli, peas, and lettuce seedlings for the past two weeks. Just leave them out for an hour or two longer each day. They were doing great and really enjoying the sunshine. Yesterday I left them out a couple hours past dark and when I brought them in they looked all wilted and just about dead! The 25mph winds beat the crap out of them and it was raining a lot too. What should I do? If they can't handle a little rain or wind how are they ever going to survive when I transplant them?