The weatherability of construction sealants was studied from the viewpoint of their waterproofing function. First, outdoor exposure tests that imposed cyclic movements of extension and compression were carried out on 12 different kinds of sealants for a duration of 10 years. The exposure sites were located in three different climate regions within Japan: Asahikawa (cold climate), Choshi (temperate climate), and Miyakojima (subtropical climate). The study used a newly developed test specimen that allowed the sealant to be exposed to a wide range of joint movement amplitudes simultaneously. The joint was moved once a month during the exposure duration. Then the depth of damage on the sealant was measured to investigate two types of damage: (a) cracking of the bulk sealant body, and (b) failure (cohesive or adhesive, or both) adjacent to the substrate. The measurement was carried out with an optical microscope and a taper gauge at positions corresponding to 0 %, 15 %, and 25 % deformation ratios. During the 10 years of exposure, surface cracking did not penetrate deep enough to split the bulk of the sealants. In some sealants, however, failures in the portion adjacent to the substrate completely penetrated the bulk, causing critical damage and loss of waterproofing capability. Furthermore, some sealants exposed in the cold climate region showed more severe failures than those exposed in the subtropical region. This result contradicts the prevalent understanding that degradation is faster in southern regions because of the more severe environmental conditions in terms of ultraviolet radiation, precipitation, and temperature. Finally, the paper proposes a method for evaluating the weatherability of construction sealants by measuring the depth of crack damage.