Turbulent boundary layers are populated by a hierarchy of recurrent structures normally referred to as “coherent structures.” Among others, ejection and sweep events are critical coherent structures of large-scale motions in turbulent flows. This study focused on gaining a better understanding of the spatial-temporal probabilistic characteristics of sweep and ejection events. The existence of uniform momentum zones (UMZs) is demonstrated to affect the spatial distribution of large-scale motions, and the ejection and sweep events tend to present near UMZ edges. On the basis of such observations, we considered the effect of UMZ edges on the presence of ejection and sweep events. In the current study, UMZ detection was employed to identify coherent structures. Several criteria for identifying coherent structures are revisited, and an integrated standard is applied to the available direct numerical simulation (DNS) turbulent channel flow data after UMZ edges were determined. Based on the integrated criterion for distinguishing ejection and sweep events, one can determine the probabilistic characteristics of coherent structures such as the maximum height, wall-normal length and streamwise length. Physical insights from DNS data such as joint probability density functions of wall-normal length and streamwise length can be established. The attached and detached features of the sweep and ejection coherent structures can then be classified and characterized, respectively. Durations of sweep and ejections events were demonstrated to follow a lognormal distribution in this study. The occurrence ratio of sweep events in the large-scale motions (LSMs) was quantified from the DNS data.