Jim Says "About Rain" the following :

"It's raining it's pouring the meana slugs will be soaring. "

Which means the slugs love the rain. They are in their glory!!!

To take care of your slugs

Potratz Carries: Slug pellets, also Deadline which is a liquid

The Plant Lady's Natural way : Use an old disposable pan, and pour stale beer into it. Slugs love it!!!