The present invention relates to a method, device and computer program for terminating a defrosting cycle within a refrigerated transport container. The container may include: a transport volume, a cooling unit comprising an evaporator arranged in a cooling space, a return air grid arranged to separate said cooling space from said transport volume, means for sensing temperature indicative of the return air temperature of air returning to said cooling space from said transport volume or the temperature of the return air grid, means for actively heating said evaporator during defrosting cycles, and a processor configured for controlling the duration of said defrosting cycles. The method includes: establishing an indicator(s) indicative of frost and/or ice build-up on said return air grid, and terminating a defrosting cycle when an indicator(s) of frost and/or ice build-up on said return air grid indicates that said return air grid is free of frost and/or ice.