Global climate change is shifting many species’ phenology and has created a number of key mismatches that threaten population persistence. Phenotypically plastic individuals have the ability to adjust their behaviour in response to environmental change. While phenotypic plasticity may serve as a buffer, it is generally not known whether in case this plasticity is insufficient there is additive genetic variation in the phenological trait so that populations’ may also show an evolutionary response. We show that hibernation emergence date of yellow-bellied marmots (Marmota flaviventer), a trait that has been significantly advancing in recent years and is associated with increased spring temperature, is phenotypically plastic. Furthermore, we used the quantitative genetic ‘animal model’ to decompose variation in emergence date and show there is significant heritable variation. We infer that so far phenotypic plasticity has allowed marmots to track the environmental changes leading to earlier emergence and suggest that in the short run, marmots may be able to continue to plastically respond to environmental change and thus that this trait potentially can evolve when the plasticity no longer buffers the selection for earlier emergence.