Abstract: Climatic condition, one of the important factors influencing tourism, affects the tourist destination and the duration. The Climatic Suitability for Tourism (CST) could be expressed as Outdoor Weather Comfort Index (OWCI) which is calculated based on China's climate features and the thermal comfort of human bodies. In this paper, taking some rice terraces systems designated in the Globally Important Agricultural Heritage Systems (GIAHS) and/or China Nationally Important Agricultural Heritage Systems (China-NIAHS) lists as examples, the daily OWCI of all sites were calculated from 1991 to 2020 and four weather comfort levels are catagorized. Then, the 30-year average of weather comfort index and comfortable days in each ten-day period, as well as the frequency of extremely uncomfortable weather occurrence were analyzed statistically. Further, the suitable tourist periods and comfort tourist periods from climate perspective for each heritage were presented. The results show that the intra-annual changes of CST in different Important Agricultural Heritage Systems of China are classified as three types: spring-and-autumn comfort type, winter-half-year comfort type and all-year comfort type. More than 10 months of suitable tourist periods in a year exist in all heritage sites and the most comfortable tourist periods range from 4 to 12 months; the climatic conditions have little restrictions on the tourism with agroecological landscape resources. The results could provide a reference for the evaluation of tourism resources potential and the formulation of tourism development planning.