Mesospheric winds from two longitudinal sectors at 53$^\circ$N latitude are combined to investigate quasi-two-days (Q2DWs) and their nonlinear interactions with tides. In a summer 2019 case study, we diagnose the zonal wavenumber $m$ of spectral peaks at expected frequencies through two dual-station approaches, a phase differencing technique (PDT) on individual spectral peaks and a least-squares procedure on family-batched peaks. Consistent results from the approaches verify the occurrences of Rossby-gravity modes ($m$=3 and 4 at periods $T$= 2.1d and 1.7d), and their secondary waves (SWs) generated from interactions with diurnal, semi-diurnal, ter-diurnal and quatra-diurnal migrating tides. We further extend the PDT to 2012$\textendash$2019, illustrating that Q2DWs exhibit significant interannual variability. Composite analysis reveals seasonal and altitude variations of the Rossby-gravity modes and their SWs. The Rossby-gravity modes maximize in local summer, whereas their 16- and 9.6-hr SWs appear more in winter, potentially originating from Q2DW-tide interactions in the opposite hemisphere.