But its raining!

Question
I've got a Tibetan Terrier puppy called Watson who's 18 weeks old.  He's been a dream to toilet train with very few accidents from day 1. We didn't even need a crate.  However the weather has just turned and it turns out he doesn't like getting his bottom wet.  He'll pee outside but then promptly comes inside waits till I'm otherwise occupied then poos.  Currently I'm taking him to the accident showing it to him, picking it up and taking it outside to where he can go and showing him again.  Any suggestions on how I can encourage him to go outside in the rain would be great.

Answer
Sarah, if he doesn't poo outside when you take him out, keep him leashed to you when you go back inside, so you can catch him before he poos in the floor, and take him immediately back outside. Showing him the mess after-the-fact is useless. He isn't able to put two and two together and figure out that you're trying to show him that the poo belongs outside. He's just a dog. LoL