Abstract: An active frost warning system for the forecasting and/or detection of active frost conditions by determining the surface or skin temperature of an active frost sensor and comparing the surface or skin temperature with outside ambient temperature and frost point temperature is provided. The system predicts active frost conditions when the surface or skin temperature of the sensor is less than frost point temperature or when the rate of cooling of the surface or skin temperature indicates that the surface or skin temperature of the sensor will be less than the frost point temperature in the future.