Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. Soil resistivity is a measure of how much the soil resists or conducts electric current. It is a critical factor in design of systems that rely on passing current through the Earth’s surface. Electrical conduction in soil is essentially electrolytic and for this reason the soil resistivity depends on: moisture content, salt content, temperature (above the freezing point 0 °C)
Because of the variability of soil resistivity, IEC standards require that the seasonal variation in resistivity be accounted for in transmission system design.Soil resistivity can increase by a factor of 10 or more in very cold temperatures.