Abstract Background The prevalence of acute aortic dissection (AAD) has been gradually increasing in recent years. This study aimed to investigate the circadian variations of AAD onset in a northwest Chinese population and provide scientific insights for AAD prevention. Methods The clinical data of 1,145 AAD patients admitted to our hospital between January 2010 and December 2020 were retrospectively collected, and the periodic features of AAD were analyzed. Results Stanford type A and type B AAD were present in 58.43% (669 cases) and 41.57% (476 cases) of the patients, respectively. The incidence rate was highest in the winter (358 cases, 31.27%) and lowest in the summer (225 cases, 19.65%). AAD occurred at the highest rate between 19:00–24:00 (321 cases, 28.03%) and the lowest rate between 1:00–6:00 (247 cases, 21.57%). Stanford type A AAD was most prevalent in the winter and the least prevalent in the spring, whereas Stanford type B AAD was most prevalent in the winter and the least prevalent in the summer. The difference between type A and type B in seasonal distribution was significant in spring (χ2 = 17.666, P