A range of elastomeric sealants has been naturally weathered for six years in a CSIRO designed cyclic movement test rig. Sealants were evaluated in a butt joint between two aluminum surfaces, and a shear joint between glass and aluminum. In general, acid-cured silicone sealants performed best; solvent-based acrylics performed as well or better than polysulfides. The performance of polyurethanes was poor. Acrylic-latex sealants are not suitable for exterior use in moving joints. Because performance of these sealants can be both good and bad, the use of sealants as the sole weather barrier must be avoided.