For at least the CPU side of things, you could use WMI.
The namespace\object is root\WMI, MSAcpi_ThermalZoneTemperature
Sample Code:
ManagementObjectSearcher searcher =
new ManagementObjectSearcher("root\\WMI",
"SELECT * FROM MSAcpi_ThermalZoneTemperature");
ManagementObjectCollection collection =
searcher.Get();
foreach(ManagementBaseObject tempObject in collection)
{
Console.WriteLine(tempObject["CurrentTemperature"].ToString());
}
That will give you the temperature in a raw format. You have to convert from there:
kelvin = raw / 10;
celsius = (raw / 10) - 273.15;
fahrenheit = ((raw / 10) - 273.15) * 9 / 5 + 32;