Moisture loads arising from the deposition of wind-driven rain (WDR) on building façades can bring about damage to wall assembly components and consequently affect their long-term performance. Hygrothermal simulations are often used by building practitioners to assess the risk to moisture damage within wall assemblies. Input of moisture loads to simulation models of wall assemblies use 1% of the WDR load deposited on the exterior surface of the wall as specified in ASHRAE Standard 160. However, results from several watertightness tests of wall assemblies have shown that the ratio between the WDR and moisture loads was highly dependent on the hourly WDR loads and driving-rain wind pressure (DRWP) acting on the wall surface. To permit correlating the varying WDR conditions with the moisture load for a vinyl-clad wall assembly, the wall was tested to a set of WDR intensities and DRWPs using a unique watertightness test apparatus, the Dynamic Wind and Wall Test Facility. The results from these tests were thereafter used to formulate an empirical relation for the moisture load based on the hourly WDR load and DRWP as variables. The moisture load for this wall type was thereafter characterized on the basis of historical climate data in selected cities across Canada. It is supposed that the information derived from this study would offer both more accurate as well as more reliable information for input to simulation models.