typedef struct _THERMAL_INFORMATION_EX
{
     ULONG ThermalStamp;
     ULONG ThermalConstant1;
     ULONG ThermalConstant2;
     ULONG Processors;
     ULONG SamplingPeriod;
     ULONG CurrentTemperature;
     ULONG PassiveTripPoint;
     ULONG CriticalTripPoint;
     UCHAR ActiveTripPointCount;
     ULONG ActiveTripPoint[10];
     ULONG S4TransitionTripPoint;
} THERMAL_INFORMATION_EX, *PTHERMAL_INFORMATION_EX;

Windows Vista Kernel Structures