Data collected from the North Pacific Ocean during September and October 1999 were combined with data from other cruises to assess seasonal differences in the relationships between sea surface temperature (SST) and methyl bromide (CH3Br) saturation. We now are able to reproduce observed saturation anomalies substantially better with the revised, seasonal CH3Br-SST equations than with those that were independent of season. The effect is most noticeable in temperate waters where data combined on an annual basis proved insufficient. The estimated, net global air-sea flux of CH3Br remains negative at -10 to -18 Gg yr-1, which is consistent with extrapolations from observations.