Abstract: Improvements in the manufacture, mounting and implementation of dry open window (DOW) structures. Such structures comprise a plurality of louvers which, when viewed in cross section, have “V” or “W” shapes that enable air to pass through a window opening while substantially preventing precipitation to pass, the precipitation instead being captured by the louvers for collection or drainage. Apparatus for mounting a DOW structure in overlying registration around the periphery of an existing window opening may include four corner frame members around and containing the DOW structure. The frame members slidingly engage, with fasteners being provided to lock the frame members to one another when they form an assembled rectangle with dimensions corresponding to the periphery around a window opening. A plurality of components are then provided for mounting the frame members and DOW structure contained therein to the periphery of the window opening.