Background The association between ambient temperature and cardiovascular diseases has been well established, but evidence of temporal changes in the risk of acute aortic dissection (AAD) onset is lacking. Methods and Results We conducted an 8-year time-series study based on data from 2120 patients diagnosed with AAD at Tongji Hospital (Wuhan, China). Daily meteorological parameters were measured in the study area. Spearman's rank correlation analysis was applied to measure the associations between daily meteorological data and air pollution indicators. A distributed lag nonlinear model following quasi-Poisson regression was used to express the nonlinear exposure-response relationships and lag effects of daily mean temperature and temperature variability on the occurrence of AAD. Considering a 25-day lag effect, lower or higher temperatures with reference to 25 degrees C did not alter the onset risk of AAD. The lag effect of daily mean temperature on the incidence of AAD is statistically significant within 2 days, and the impact of daily mean temperature on the risk is most influential on the day. The exposure-response curve between daily mean temperature and onset risks of AAD at lag 0 showed that the extremely cold temperature (2.5th percentile, 0.5 degrees C) significantly increased the AAD risk for the total (relative risk, 1.733; 95% CI, 1.130-2.658) and type A dissection (relative risk, 3.951; 95% CI, 1.657-9.418). Temperature variability within 1 week did not affect the onset risks of AAD for the total. Conclusions We confirmed that extremely cold temperatures significantly increased the AAD risk, which could contribute to early prevention and timely diagnosis of the disease.