Abstract: A temperature compensated pressure switch (“TCPS”) with thermal lag compensation, trend indication, and forecast analysis. The TCPS has a first control unit, a pressure sensor connected to the first control unit outputting a first pressure data, a temperature sensor connected to the first control unit outputting a first temperature data, and a first storage unit connected to the first control unit storing: minimum and maximum pressure data corresponding to temperature data and rate of temperature change values. The first control unit can substitute a second temperature data, for the first temperature data for a period of time. The first control unit also outputs a first signal indicating the amount of material is acceptable when the first pressure data is above the minimum pressure data and outputs a second signal indicating the amount of material is unacceptable when the first pressure data is not above the minimum pressure data.