A study was realized to assess the effects of historical and projected future climates on the hygrothermal performance of cross-laminated timber wall assemblies in 12 Canadian cities belonging to several climate regions and zones and for two cladding and ventilation types. Water ingress in the wall assembly was supposed to be 1% wind-driven rain (WDR), and the airflow rate in the drainage cavity was calculated using local climate data. The hygrothermal simulation results showed that under the assumption of no deficiencies allowing wind-driven rain to enter into the wall (perfect wall), there is no risk of mold growth in the future for both claddings, either vented or ventilated. Under the assumption of high moisture loads (1% WDR), the mold growth risk could increase significantly in all climate regions and cities considered. However, in those cities located in the Cordillera and Prairie regions, the increase was not found to be problematic as the maximum mold growth remained under the acceptable level, whereas for cities located in coastal and southeastern regions, the increase in mold growth risk could be considerable. The impacts of cladding and ventilation types on the relative performance of the walls varied with city location.