In reply to Sparky121:
My clothing system for everything from year-round UK rock climbing* to summer in the Alps: long-sleeve synthetic T-shirt, thin merino long johns, very thin softshell jacket and trousers, and a lightweight mid layer if it's cold enough (I have a Nano Air, but a fleece or a woolly jumper would work equally well). I usually wear a Buff as a hat/sun protection, and will have gloves/etc if needed. I'll also likely have a warm belay jacket in my bag in anything but the most benign conditions - it's useful to keep warm when you stop moving, and very useful to keep warm if you stop moving because you've broken yourself.
The only things that change for winter are that the softshells are replaced by thicker (ie much more windproof) softshells, the Buff will probably be replaced by a thin woolly balaclava, and gloves (and spare gloves) will be essential.
I never take waterproofs anymore unless the forecast is for a huge amount of the wet stuff to fall from the sky. Practically that means my waterproofs only see the light of the day in UK summer, because if it's forecast for torrential rain in winter or in the Alps we almost certainly won't be out playing in it.
* - unless it's a blazing hot summer day. In which case a disgusting colour clash of shorts and T-shirt is mandatory.