Cimorene

If he keeps doing it, it might be worth taking him to the vet to make sure he doesn't have a UTI or anything. Sometimes they can make dogs have unusual pee habits. Also, since it's so cold and he's older, he may be having arthritis pains and there might be some kind of anti-inflammatory he could have that would help.

All that said, maybe just start having a designated 'late night toilet' area with puppy pads or newspaper, so that if he does really have to go at least there's a place? (Though it sounds like he's like Pirate, who is HORRIFIED at the idea of going anyplace in the house. The one time he had an accident because his stomach was terribly unhappy, I swear if he could've cleaned it up himself, he would have.)