One of Wim Hof's many cold training methods includes walking and meditating barefoot in shorts for 30 minutes up to an hour inside a freezer room (± -20°C with heavy winds).
Wim Hof is famous for breaking numerous records relating to cold exposure giving him the nickname "The Iceman". One of his many Guinness Books of Records is standing in a container while covered with ice cubes for more than 112 minutes.