The Roon is a framework for architectural orientation that we know from Iranian architects through the introduction of Professor Pirnia, who considers the traditional architecture of Yazd to be in a specific direction due to climatic conditions. The purpose of this article is to examine the accuracy of this theory so that, while examining and criticizing one of Pirnia's theories and recognizing aspects of traditional Iranian architecture, we can identify the climatic situation of Yazd in terms of architectural design. Is the traditional architecture of Yazd really designed based on the northeast-southwest orientation and the climatic situation? What is the optimal direction for architecture and urban development in this climate? In this research, after explaining this theory and addressing the importance of the issue of orientation in the design of sustainable architecture and the climate of Yazd and the effective factors, the stretch of the courtyards of houses in the aerial map of the 1930s was examined analytically and the frequency of historical houses of the Qajar period in Yazd in this orientation was measured quantitatively. The results obtained show that the Roon proposed by Pirnia (northeast-southwest stretch) is rarely found in the aerial map of Yazd city, but the orientation of the main aspect of the most prominent Qajar houses in Yazd is closer to the straight Roon (facing southwest), which simultaneously allows adequate light to reach the sunny front of the building in winter and protects the wintering space from the undesirable cold and winter wind.