The present method is based on the fringe shifts of interferograms from different ray directions around the temperature field. The contour of the temperature field is obtained from the envelopes drawn at the boundary of each fringe shift. The temperature are evaluated by solving the simultaneous equations of the first degree for the unknown refractive indices at the grid points in the contour of the temperature field. The method has been applied to the temperature fields of natural convection caused by heated plates as well as to those of heated-air jets with rectangular exit. The results have been compared with the temperatures measured by a thermocouple. It is found that the present method may be useful in evaluating temperatures and/or densities in some complex fields.