A numerical computation of the rate of temperature change at different frequencies in different biological tissues is analysed. The induced electric field within the tissues and thereafter specific absorption rate (SAR) are calculated and studied. Then the corresponding rate of temperature change in various tissues at the corresponding microwave frequencies is then assessed. This change in temperature can heat the tissues with passes of time. As this change of temperature in different tissues can be limited by the thermoregulatory system of the biological body at some extent but the minimum distance of the transmitters from the crowded area must be recommended and should be followed strictly.