Abstract: Provided is a cover for a window-mounted air conditioning unit that is affixed to a window to prevent cold air and precipitation from entering into a home through any exposed areas within the front portion of the window-mounted air conditioning unit. The cover includes a face portion and four sidewalls with a multi-layer construction. Preferably, the layers include an interior layer for wind blocking, a middle thermal insulation layer for insulation, and an exterior layer for durability. The face portion is substantially rectangular and has an outer edge therearound, wherein the four sidewalls extend perpendicularly along the outer edge forming a pocket on the opposite side of the face portion. The pocket is configured to receive the front portion of an air conditioning unit front portion.