E region real height determinations for 2.2 MHz has been carried out using standard electron density (N(h)) profiles from Maeda's rocket observations and the International Reference Ionosphere (IRI) models for application to the Saskatoon (52¿ N, 107¿ W) MF radar. A comparative study of the virtual and real heights for the totally reflected signals, for both solar maximum and minimum conditions, reveals that these heights increase from solar maximum to minimum. The group retardations from rocket N(h) are found to be lower than that of the IRI models in all the seasons. During summer the noon time virtual heights are very similar for the IRI model and MF radar data, but during the winter the IRI virtual heights are considerably lower than the observed heights. The derived group retardations are added to the mean wind and tidal climatologies for Saskatoon. This enables the prediction of the heights up to which the winds and tidal data can be taken without any correction for group retardation. ¿ American Geophysical Union 1993