Tourism has become one of the sectors which are the mainstay source of foreign exchange in Indonesia. One of the region which has tourism potential is Samosir District at North Sumatra Province. Climatic conditions affect the tourist comfortability while doing the tourism activity. Studies on climate comfort in Toba Lake Region, especially in Samosir District have not been done. Way to determine the level of comfort associated with tourism activities are known to the Tourism Climate Index (TCI). This research aims to determine the level of climate comfort tourist destinations in Samosir District based on the value of TCI and knowing the relation between TCI value with the number of visits a tourist destination. © The Authors, published by EDP Sciences, 2019.