The review emphasizes that there are multiple pathways to diapause completion. The programmed course of events is modified by environmental cues. Often chilling is not a prerequisite for the completion of hibernation diapause (examples tabulated). Diapause completion progresses well at intermediate or high temperatures, sometimes it is even stimulated by high or increasing temperature. Low temperatures are important, as they (1) conserve metabolic reserves, (2) prevent resumption of post-diapause morphogenesis and thus synchronize the life-cycle, (3) represent contrast to the later increase in temperature. Diapause consists of phases with different prerequisites. There is a principal difference between diapause development and photoperiodic activation as indicated by the subsequent physiological condition of insects.