#compdef -value-,TZ,-default-

local expl

if (( ! $+_zoneinfo_dirs )); then
  _zoneinfo_dirs=( /usr/{share,lib,share/lib}/{zoneinfo*,locale/TZ}(/) )
fi

_wanted time-zones expl 'time zone' _files -g '[A-Z]*' -W _zoneinfo_dirs "$@" -