The recently measured magnetic dipole (M1) absorption intensities of rovibronic transitions in the A-band (b1Σg-X3Σg-, 0–0 band) of 16O2 are theoretically analyzed employing a model in which the b1Σg:X3Σg- mutual perturbations are treated to a sufficient degree of accuracy. Effects of rotational perturbations became manifest in the data analysis and rovibronic correction parameters are needed to reconcile theory and experiment. At a subtle level there is evidence of Herman–Wallis (HW) type effect arising from vibration– rotation interaction in the b and X states. The functional form for the HW correction factor is arrived at from first principles. The final calculations reproduce the measured intensities to fraction of a percent, well within the measurement accuracy. The present analysis leads to the value <M1>0;0=0.02679(4) μB for the M1 transition moment, and the spontaneous emission rate (Einstein-A coefficient) Γ0.0=0.0874 s-1. For the sake of completeness, the electric quadrupole (E2) contribution to the observed intensities is also quantitatively assessed.