I have updated bfx. BfX_C does now incorporate humidity. Furthermore the function BfX_AD has been added with which you can calculate air densities. Also, BfX can convert between more units - see BfX_help2. The "getting started" spreadsheet shows it all.
In fact this is an early release, the getting started spreadsheet and the site will be worked upon further. Foremost it will discuss the effects of atmospheric conditions. Also a detailed comparision of BfX calculations with radar measurements on Lapua bullet trajectories will be made.