What should be monitored regarding the aircraft skin temperature for deicing to be effective?

For deicing to be effective, it is crucial that the aircraft skin temperature is above freezing. The reason for this is that deicing fluids need to work optimally at certain temperatures to ensure they can effectively remove ice and prevent further accumulation. When the skin temperature is above freezing, the deicing fluid can properly spread and adhere to the surfaces of the aircraft, effectively melting and removing existing ice or snow.

If the skin temperature is at or below freezing, the deicing fluid may freeze upon contact or fail to adhere properly, limiting its effectiveness. Additionally, room temperature and consistently below-freezing skin temperatures do not provide the necessary conditions for deicing materials to function effectively, resulting in potential operational issues and safety risks during flight.