Replaying the game but I can't recolour my dog's jumper this time...

Exactly as the title says. First time I played the game I was able to add a paint colour to doggy's jumper (the cute hoodie he wears in the rain 🥺) and this time round it won't let me. I've come up with two possible reasons why - either it was a glitch in my first save and it shouldn't have been an option at all, or I should wait until the next day it rains and try customising again before choosing a location.

I'm doing a whole colour scheme thing with my hut, and it would be nice if his jumper was coordinating. Bit nitpicky I know but it already bothers me that you can't paint every single thing you want to add to the hut. I'm doing my best, people.