The present invention relates to an on-site mobile facility for shielding from wind exerting a wind load on the facility, rain or snow when constructing, renovating or assembling a building, a bridge or a wind turbine, the on-site mobile facility covering an area having boundaries and corners, comprising: a plurality of modules, each module having a module roof structure, the module roof structures being mounted as a facility roof structure connecting horizontal beams of the module roof structures, the facility roof structure having edges and the horizontal beams defining the edges which are supported by legs, the legs and the beams defining side areas, the side areas being covered by a shielding arrangement, the shielding arrangement of the side area comprising elongated elements, and cover material, such as tarpaulin, being arranged between the elements and connected therewith, wherein the on-site mobile facility further comprises a guide system for guiding the shielding arrangement of the side area, the guide system being slidably connecting the elements with one of the beams or the adjacent legs so as to at least partly uncover the side areas, so that wind is allowed to pass through the facility by passing through the uncovered part of the side area and out through an uncovered part of the side area on another side of the on-site mobile facility to reduce the wind load on the facility in order for the facility to remain unaffected by the wind load during heavy winds. The present invention also relates to a facility mounting method for mounting the on-site mobile facility according to the present invention.