Observed spectra of 16 CH₃OH transitions towards W3(OH). The quantum numbers and rest frequencies of transitions are labelled in their respective panels. ClassI and II CH₃OH maser transitions are labelled in red and blue, respectively. Their Gaussian fitting results are plotted in the corresponding colour. The transitions that have no maser detection yet are labelled in black, and the Gaussian fitting results are plotted in green. The vertical magenta dashed line represents the systemic velocity of V_LSR = −46.19 km s⁻¹.