Weathering testing of sealants and adhesives is critical to understanding how these materials will perform in outdoor environments. A wide variety of natural outdoor and accelerated weathering test standards are used to evaluate sealants’ performance in service environments. These tests can range from simple short-term testing for quality control and validation purposes to more scientifically robust standards that seek to provide realistic reproduction of weathering effects observed outdoors. Most commonly used weathering test standards for sealants and adhesives include general test cycles for durable materials that may not accurately simulate outdoor performance. Although pass/fail and correlative testing both provide invaluable information, organizations conducting testing often have a goal to determine an acceleration factor between laboratory and outdoor testing that enables prediction of materials’ service lifetime. Historical weathering test standards have done a poor job of replicating outdoor environments, particularly in regard to the effects of water on sealant durability. This has hampered efforts to use weathering testing to determine service life. This paper discusses efforts to bridge the gap between modern comparative weathering testing and service life prediction.