I echo past contributor's comments about a 8-yard-style, 16 oz wool kilt. Further, tall boots and/or tall wool socks are very helpful as well as keeping my core, head, hands, feet warm. I also wear thigh-length merino wool boxer briefs. If temperatures creep below -10C, then I'll wear merino wool leggings and scrap the boxer briefs.

Guluck,
Jonathan