Are lightweight ski socks warm enough for winter skiing?

Yes, for most winter resort conditions (15-32°F / -9 to 0°C), lightweight merino wool socks keep feet warm by managing moisture effectively and avoiding the circulation restriction that thick socks cause in snug boots. Dry feet are warm feet. If your boots fit properly, lightweight socks are often warmer than thick ones. For temperatures consistently below 10°F (-12°C) or if you have genuine cold sensitivity unrelated to circulation, consider midweight socks.