Temperature
Temperature and electrical resistance are closely related. As temperature increases, electrical resistance will decrease; this also is true for the inverse. The parameters and minimum/maximum acceptable IR test values are based on fixed reference temperature, the IR test numbers have to be corrected (to the reference temperature) to be made any sense of.
Humidity
The amount of moisture in an environment will also affect the IR test measurements. The lower the moisture content in the air, the higher the IR test reading. The inverse is also true, so when possible, IR tests should not be carried out in very humid atmosphere. Because there are no standard formulas to adjust for humidity, you should record the relative humidity of each IR test to be used as a comparison when engaging in traditional IR testing.