Yes, wasn't even thinking about the weather. Just start doing it indoors when it gets cold and you will be spending way more time outside anyway. And just make it part of the routine to have them sit on the potty before they get dressed for outside.

I have one dcg that is almost finished potty training and all the rest are potty trained. So it is just part of the routine that we don't leave the house until everyone has gone. But I always take my portable potty with me if we are going far from the house, because someone almost always has to go when we are out.