The present overhead network for Port-Harcourt city does no only present a shabby appearance and unreliable distribution system but unfit for the present demand in terms of bulk power transfer and telecommunication interference. Underground distribution network is primarily a matter of heat transfer from cable core where the heat is generated, through the cable insulation to the surrounding medium and finally is discharged from the surrounding medium. This study therefore presents the subsoil temperature at various periods of the year and at depth of 20, 50, 80 and 100cm. Ten locations were chosen in Port Harcourt City, and in each location the soil temperature was taken at the given depths within the months of March, September and November. These months represent different seasons of the year. The effective discharge of heat to the surrounding environment is due to the condition of the soil (moisture content, grain size etc.,). Therefore, soil resistivity test was also conducted. These results were analysed and the variation of temperature within the year at various depths were known. This will enable designers to calculate proper rating of underground cable laid at different depths.