Lately my dog had constantly been very grumpy and mean to everyone. He was never like that before:eek: .he used to be so nice. (I don't know if this might do with it, but he's a jacck russel- border chollie.) what could be wrong with him?

I think the first step is the vet. You can't rain away a physical problem. You also need to look at how old he is, and what may have changed to cause it. With some more details, we may be able to help more.

And I believe that labman meant: you can't Train away a physical problem.

Yes, if only taking them out in the rain did work.