Atmospheric conditions play a key role in the evolution of aircraft wake vortices. Workers in the European S-Wake program have proposed the introduction of discrete 'wake vortex behaviour weather classes' (WVBC) in which vortices are expected to exhibit differing evolution characteristics. As part of a broader study we have established climatologies with respect to these WVBC for a variety of airports worldwide. We have used the Met Office Site Specific Forecast Model to calculate vertical profiles of meteorological variables over a seven year period. Synoptic data from each site and forcing data from the ECMWF ERA-15 re-analysis project were used as input to the model. The profiles were used to evaluate the mean WVBC at each site on pressure levels up to a value corresponding to a height of around 2km. The implications of the results for future wake vortex separation rules are discussed.