The present application relates to a welding helmet comprising a helmet housing and a head cover adapted to be worn on a wearer's head and made of an air-impermeable and flexible material, wherein a zipper arrangement is provided between the helmet housing and the head cover to detachably connect the head cover to the helmet housing around the whole perimeter of an opening of the helmet housing, and wherein after the head cover is connected to the helmet housing, the zipper arrangement is located within the housing of the welding helmet. The present application also relates to an assembly having the welding helmet.