SNAILS AND SLUGS
Don't you love a weather pattern that encourages slugs and snails? It appears the garden gods are against you! There's nothing snails and slugs like so much as damp conditions!
The best way to deal with slugs and snails is probably to trap them. They hide in debris and dark sheltered places, so the idea is to trap them at their own game. You can use boards, grapefruit halves and flowerpots to accomplish this. The snails and slugs will hide under and inside these traps. You have to then remove them from their hiding place and destroy them. Perhaps you can use a tub of ammonia solution or salt water to dump them into.
The other thing that works quite well is diatomaceous earth sprinkled around your vulnerable plants. Here is an explanation given by the University of Vermont Extension:
"Diatomaceous earth (silica) is a naturally occurring mineral made from fossilized remains of marine organisms. These fossilized particles are extremely small in size and have sharp edges. In theory, when insects come in contact with diatomaceous earth, these sharp edges cut and remove the waxy cuticle on their exoskeletons, which leads to their dehydration and death."
You can usually find diatomaceous earth at any garden center. I would say this is the way to go. However, it wouldn't be practical to put it everywhere, so perhaps this in combination with traps would be a good solution for you.