A system for determining a tissue temperature comprising: a first thermocouple and a second thermocouple spaced circumferentially apart in a catheter; an external control unit electrically coupled to the thermocouples and to the catheter; the external control unit configured to apply a power to a first tissue through the catheter; the external control unit configured to measure a voltage from each thermocouple; and the external control unit configured to calculate a first tissue temperature based on the thermocouple voltages; and characterized in that the external control unit is configured to: calculate an absolute difference of the thermocouple voltages; generate a compensation temperature based on the power and the absolute difference of the thermocouple voltages; calculate a temperature of each thermocouple, and calculate a compensation temperature, ct, from the equation: ct = pc × p + tdc × td + c wherein, pc is a power constant, p is the power measured in watts, tdc is a temperature delta constant, td is the absolute difference of the temperatures measured in degrees Celsius, and c is a constant; calculate a bounded compensation temperature, bct, from the equation: bct = 0 for ct < 0; bct = ct for 0 ≤ ct ≤ 15; and bct = 15 for ct > 15; calculate a temperature of each thermocouple based on each voltage; calculate tmax, a maximum of the thermocouple temperatures: the external control unit calculates a regulation temperature from the equation: rt = bct + tmax; and regulate the power to the first tissue based on the regulation temperature. a first thermocouple and a second thermocouple spaced circumferentially apart in a catheter; an external control unit electrically coupled to the thermocouples and to the catheter; the external control unit configured to apply a power to a first tissue through the catheter; the external control unit configured to measure a voltage from each thermocouple; and the external control unit configured to calculate a first tissue temperature based on the thermocouple voltages; and characterized in that the external control unit is configured to: calculate an absolute difference of the thermocouple voltages; generate a compensation temperature based on the power and the absolute difference of the thermocouple voltages; calculate a temperature of each thermocouple, and calculate a compensation temperature, ct, from the equation: ct = pc × p + tdc × td + c wherein, pc is a power constant, p is the power measured in watts, tdc is a temperature delta constant, td is the absolute difference of the temperatures measured in degrees Celsius, and c is a constant; calculate a bounded compensation temperature, bct, from the equation: bct = 0 for ct < 0; bct = ct for 0 ≤ ct ≤ 15; and bct = 15 for ct > 15; calculate a temperature of each thermocouple based on each voltage; calculate tmax, a maximum of the thermocouple temperatures: the external control unit calculates a regulation temperature from the equation: rt = bct + tmax; and regulate the power to the first tissue based on the regulation temperature. calculate an absolute difference of the thermocouple voltages; generate a compensation temperature based on the power and the absolute difference of the thermocouple voltages; calculate a temperature of each thermocouple, and calculate a compensation temperature, ct, from the equation: ct = pc × p + tdc × td + c wherein, pc is a power constant, p is the power measured in watts, tdc is a temperature delta constant, td is the absolute difference of the temperatures measured in degrees Celsius, and c is a constant; calculate a bounded compensation temperature, bct, from the equation: bct = 0 for ct < 0; bct = ct for 0 ≤ ct ≤ 15; and bct = 15 for ct > 15; calculate a temperature of each thermocouple based on each voltage; calculate tmax, a maximum of the thermocouple temperatures: the external control unit calculates a regulation temperature from the equation: rt = bct + tmax; and regulate the power to the first tissue based on the regulation temperature. the external control unit calculates a regulation temperature from the equation: rt = bct + tmax; and regulate the power to the first tissue based on the regulation temperature.