Abstract: Variations in the relative humidity of the air present within a housing of a scale, particularly a high accuracy scale utilizing a capacitive transducer mounted at the interior of the housing, are controlled by a combination of (i) a mechanical partial seal of the housing which resists a flow of moisture (by diffusion and air flow) through the seal, and (ii) a supply of a desiccant located within the housing which both absorbs and desorbs moisture from the air held within the housing. The partial seal is preferably located at an opening in the housing for a shaft mounting a weighing pan external to the housing. For low motion, a face seal of a few mils provides the appropriate flow resistance. For high motion or low capacity scales, the partial seal is a radial seal formed by the shaft and a surrounding sleeve mounted with a small annular clearance is used. The desiccant is preferbly silica gel.