I wear wool poly blend thermal tights, under loose fitting polyester warmup pants. Keeps the wind out, the warmth in, breathes nicely, is comfy, and doesn't look out of place in public. I have stayed comfortable wearing this in sub zero temps and windchills down to about -30 F. In a strong headwind in these conditions, a barrier over the crotch (stocking cap under the pants works nice) keeps things from freezing down there.