-20 is very cold...if your hands are out in it for about 5 mins they turn very very numb, your movemensbecome slow, speach slurs and concentration drops (if exposed long enough). When you go back inside from the cold they turn very red quickly with the returning blood flow, that in itself can be painful. The coldest i've had is -35o windchill on Glas Moal (Glenshee) that was 50mph sustained wind and snow crystals hitting your face. That was like hundreds of needles hitting your face, to be honest if i was naked i'd have passed out and died in about 2 mins! Its really not nice, cold snowy weather is pretty but people dont understand the dangers, they think its all about records being broken but it is a very real threat if you are out in it and nt prepared. You should go to Cairngorm or Glenshee for the day so that you can experience it...its definately worth the time, especially in your own country!