A three dimensional (3D) stack of phase change memory (PCM) devices which includes PCM devices stacked in a 3D array, the PCM devices having memory regions; a memory management unit on at least one of the PCM devices; a stack controller in the memory management unit to monitor an ambient device temperature (Tambient) with respect to a neighborhood of memory regions in the PCM devices and to adjust a programming current with respect to at least one of the memory regions in the neighborhood of memory regions in accordance with the Tambient. Also disclosed is a method of programming a PCM device.