We focused on the traditional processing method which generates the superior quality of Yamato-shakuyaku. First, we assessed the historical literature written around Edo and Meiji period and rediscovered the traditional air drying method still inherited in Nara Prefecture. Then, we gathered and analyzed the data of medicinal plants production in Nara Prefecture among 1938 and 2019, and investigated the decline of local production and experienced agricultural techniques of peony through the transition of its yield. In order to visualize the ancient knowledge of crude drug manufacturers that contributes to the instruction of the skills for supply of seedlings, cultivation, and processing, we settled the meteorological observation devise at the outdoor drying shelf for 3 years, and recorded the real drying environment. When comparing the meteorological data with other cultivating area of peony using the estimated values of Agro-Meteorological Grid Square Data, the climate of Nara Prefecture was with high temperature and low humidity than other areas, and it seems to be quite suitable for air drying with adequate topography. The wind rose calculated by measured values of wind direction and wind speed showed the wind conditions in Nara that west wind was frequent in daytime and wind conditions are mildly but diversely changing. Among other producing areas of peony, the mechanical drying is major, whereas air-drying with low cost utilizing local environment features is still applied in Nara. We revealed the rationality of traditional methodology by digitization of meteorological factors which can be high added value.