Accelerated weathering of coatings for wood by QUV-A with direct water spray closely approximates natural weathering by simulating the erosion and cleaning typical for exterior coated wood, increasing the moisture content of the wood above what is typically found in accelerated test procedures, and subjecting the coating to a much greater thermal shock than condensation methods. This paper examines the performance of various exterior wood coatings under this modified QUV test method. Coatings for exterior millwork such as exterior siding, decks and doors require distinct performance properties such as excellent light stability, high flexibility and freeze/thaw cycling properties. New waterborne (WB) UV-curing cosolvent-free polyurethane dispersions (PUDs) were developed to provide excellent exterior weathering properties, high flexibility, enhanced water resistance and improved adhesion to difficult substrates such as wood and plastic. This paper describes unique curing capabilities of WB UV PUDs, attributes and performance properties, and weathering results using an innovative accelerated weathering tester designed to simulate outdoor weathering of exterior wood coatings.