mountaineering and particularly values the La Sportiva double boot in frigid weather.
When deciding between a lightweight boot and a double boot, the most important things to consider are altitude, season, and weather conditions. Breaking a trail when snow is deep can be extremely cold on the toes, particularly in wetter climates, and a double boot is essential for any lengthy slog through fresh snow.
Another consideration is whether the hike involves camping or is in a location such as the European or New Zealand Alps, where mountain huts are common and day excursions are taken. If it is possible to comfortably dry out boots at the end of the day, then the lighter and more flexible single boot may be best. It pays to be conservative, however, and choose the double boot if it is possible that cold, wet weather becomes a major factor.