Theoretical calculations on multifluid solar wind have indicated that the velocities of ions of the same element are not the same in the inner coronal region where the freeze-in process of these solar wind heavy ions occurs. This may have nonnegligible effect on the inference of the electron temperature in this region from the observed ionic charge states. In this paper, we investigate the effect of differential ion velocities on the inferred freeze-in temperatures and the coronal electron temperature diagnostics. We then investigate if the ionic charge state data are able to provide constraints on the differential velocities of these ions in their freezing-in region. We use the ionic charge composition data observed by the SWICS, instrument on Ulysses during the south polar pass as an example. ¿ 1998 American Geophysical Union