How long can I stay outside when its 20 degrees and snowing

Its 20 degrees out and I want to know about how long I will survive outside.

as long as you want so long as you are dressed properly

twenty degrees Fahrenheit is the average temperature for January and February, just south of Oslo Norway, where I live. Children are playing outside at kindergarten, people are jogging, walking ... life is pretty much the same as in the summer. No restriction at all.
When it gets neas 0 degrees Fahrenheit then it is time to think about restricting the time we are outside but still, I have been skiing in the mountains, for hours, in temperature below 0 F and ... I am still alive! ;-)

Bundle up, including water resistant hat that covers your ears, and heavy winter gloves. Also, wear warm boots and two pair of heavy socks, and keep moving because your feet and hands will get cold. It's not so bad. I have a neoprene ski mask like the one in the link below which I use when the weather gets below 0. I've had it on at -15, when I had to fight my eyelashes sticking together because the moisture in your eyes freezes, making your eyes tear, and then the tears freeze on your eyelashes, freezing your eyes shut. I'm not going to lie to you, at that temperature it is miserable and you really have to keep moving not to freeze.