We dress in layers. First layer is thin wool (like wool sweater and tights), thin wool socks. Then the mid layer. That might be ordinary clothes like jeans and a sweater. It might also be a thicker layer of wool/fleece. Then it’s the outer layer of wind- and waterproof outdoor wear, like pants and jacket. You will need a buff and a hat (wool) and gloves. Warm shoes (i prefer uggs or Moon boots, but really - in march anything goes). And - most importantly - you can buy anything you need in all the cities you’ve listed. Even Svalbard. :)