As winter approaches, layering becomes even more important. In the past we’ve reviewed a variety of synthetic and down layers that offer lots of insulation – but when it’s cold, I often also want a additional warm layer I can wear all day over my base, both for the additional warmth but also the flexibility – so that I can remove my padded insulating jacket when working hard on an ascent without getting too cold. The main things to consider are warmth, breathability and drying speed (both the material and venting features such as zips). Does the garment fit easily…