Climatic comfort or human thermal comfort has a far-reaching impact on human settlements and human activities. A number of thermal indexes are widely applied in the fields of architectural design, urban planning, human health, and tourism development. As an indispensable and critical part of climatic comfort assessment, scale of thermal sensation not only greatly affects the validity of a thermal index, but also makes the comparison among different thermal indexes possible. At present, a few traditional scales of thermal sensation are generally used for the climatic comfort assessment in different regions without any localized adjustment. Alternatively, experimental investigation and questionnaire survey are adopted to formulate the scale of thermal sensation for a certain area. Therefore, a new approach named "seasonal anchor method" is proposed in this paper, which includes 4 steps --"grading, naming, anchoring, and projecting". Furthermore, based on the long term daily meteorological data (from 1981 to 2010) from 814 national basic meteorological observing stations throughout China, a case study is carried out. In this study, a 7-level scale of thermal sensation, which includes "torrid, hot, warm, neutral, cool, cold, and frozen", is proposed. Meanwhile, the threshold values of each level of thermal sensation for THI (temperature and humidity indexes) and WEI (wind effect index), which can be adopted as a national standard, are generated. Finally, climate-comfortable period and climate-uncomfortable period in China are evaluated, which brings us some meaningful discoveries.