If you put it outside and it’s -20 C out there?
I think you’d be better off putting it in a bowl of ice water than just outside in cold air. I think in ice water it would chill in about 15 minutes or so, but I may be mistaken.
If you’re dead set on putting it outside, and you have any snow in that minus-20 backyard, shove it into a pile of the powdery stuff for 15-20 minutes.
according to my wine book you should serve wines slightly warmer in the winter, but no warmer than 10 degrees C, and no cooler than 5.
so 8 minutes in a bucket of ice, water and salt, or 5 minutes outside would do!
Depends on the wine, though! If its a white, you want it colder than if its a red! Reds should be served around 15-18deg Celcius, while whites should be colder.