going potty in the house

Sam has done ok with his potty training until last night I put him out and he came in and pooped on the floor. Sometimes that happens so I put him out again. Well right when he came in he peed! SO I put him out AGAIN and cleaned it up. Well about a half hour later he peed in the house again.

Today my mom said he was just horrible peein' left and right. We watch him and he just all the sudden squats and pees. It's driving me nuts because I thought this was going pretty well. I think it's because of the bad weather and he doesn't want to go outside. But he can't be doing that every time there's bad weather. Advice?