In reply to AnnaSpanna:
I usually ski in my climbing kit:
Cheap but effective thin Mountain Hardware showerproof jacket
Cheap over trousers (or old snowboard trousers)
Long sleeve thermal 't-shirt'
Old M&S jumper or an old fleece
Hat, gloves, goggles/glasses
That's usually ok down to -15 or so more if the sun is out.
Facemask, Ronhills, one or two extra jumpers and a scarf when it's cold or crappy.
If you're keeping moving and the sun is out you don't need much at all to stay warm. If you're spending a lot of time in bad weather or on open chairs or standing about in ski-school then you'll get cold. Cold fingers and toes are the most unpleasant I find, keep them warm and dry and you'll feel better.
jk