Oil fully up to temp after only 3 to 6 minutes from a cold start in the winter?I actually did some temperature testing and reported my findings on this thread: Foxwell NT530 - new user info and questions
As I found there, the oil is up to "final" temp in 3-6 minutes in cold weather. So while time isn't the ideal way to determine that the car is warmed up, the coolant gauge is reasonable (when it's up to temp, the oil is close enough to fully warmed, IMO). But even without the coolant temp gauge, 3-6 minutes is not a reasonable amount of time, even in cold weather... with just city driving (and shifts keeping below ~3k RPM).
I'm in full agreement that idling the car to warm it up is not a great idea. Start the car, wait a little if you want, and then drive off. Don't rev the hell out of it, and don't WOT during this time. That's what I'm seeing, and I've been doing that for years on all my cars with no ill effects.