Just wear either wind-proof or insulated relaxed-fit long pants. The air between the skin and loose-fit clothing forms a layer of insulation, but if you suffer from low-blood circulation, insulated pants like the casual wear and relatively inexpensive ones sold at Costco and other stores could help. Skin-tight clothing are the worst wear to keep your body warm. Wear layers of synthetic garments underneath a windproof outer jacket or parka, and don't forget a scarf, stocking cap, gloves, and moisture-resistant boots that have room inside for wearing a pair of warm synthetic-wool blend socks. Never wear boots or shoes that fit tightly on your feet (you want lots of room for thick and warm synthetic socks). Enjoy the cold winter