Abstract: Based on the Modern-Era Retrospective Analysis (MERRA) for research and applications reanalysis data, this study analyzes the classification of stratospheric final warming (FW) that considers the stratosphere and lower mesosphere. Our study reveals that the seasonal shift from westerly to easterly wind in the circumpolar zonal wind is not exclusive to the stratosphere but also occurs in the lower mesosphere. Furthermore, the polar-mean air temperature and circumpolar zonal wind displayed robust interannual variability in spring within the lower mesosphere, which is comparable to that within the stratosphere. This suggests that FW events are not limited to the stratosphere but also manifest in the lower mesosphere. We also identified the annual FW onset date at each pressure level. Our findings indicate that the average onset date of FW events varies from April 7 to 27 at different pressure levels, with a standard deviation varying from 11.3 to 18.3 days. The latest onset occurs at 1 hPa, while the minimum standard deviation occurs at 0.1 hPa. According to the vertical profile characteristics of the FW onset date, this study classifies the FW events into three types: simultaneous, successive, and climatology-like. In the simultaneous type, FW occurs almost simultaneously at all levels, from the mid-stratosphere to the lower mesosphere. This occurrence is accompanied by a reversal of the sign of polar-mean geopotential height and temperature anomalies. Strong planetary wave activities dominate the simultaneous onset process. The onset process of the successive type bears a resemblance to that of the simultaneous type, albeit with considerably weakened planetary wave activities during the FW onset. Here, the non-adiabatic heating of solar radiation plays an important role. In the climatology-like type, the occurrence of an FW event at 10 hPa is primarily driven by dynamics. After the occurrence of the FW event in the mid-stratosphere, the planetary wave activities are suppressed in the upper stratosphere, leading to FW events at these pressure levels being primarily induced by non-adiabatic heating. The FW onset at 0.1 hPa can be explained in two possible ways. One explanation posits that the 0.1-hPa FW onset may be driven by nonadiabatic heating. Alternatively, for some FW events, secondary planetary wave activities following the FW onset in the stratosphere may lead to the onset of FW at 0.1 hPa.