Abstract In Mediterranean climates, amphibian larvae often occupy temporary ponds where they must avoid deleterious temperatures and develop before these ponds dry out. We measured thermal heterogeneity in one of these ponds and discussed its relationship with development time and thermal tolerance in three observed species. We found large daily thermoclines that may reach 14°C and persist into the early evening. To our knowledge, this is the first time that such a large degree of thermal heterogeneity has been reported in temporary ponds. Thus, we raise hypotheses linking thermoregulation, habitat use, and growth that Mediterranean amphibian larvae, or other aquatic larvae inhabiting water bodies with strong thermoclines, might exhibit. We argue that studies on thermoregulation of larvae are badly needed to help us understand the responses of Mediterranean amphibians to global warming.