Thermal thresholds for seed dormancy release and germination are important tools for predicting germination timing. Orrù et al. study germination in seeds of Vitis vinifera subsp. sylvestris collected from four populations from between 100 and 800 m above sea level and apply a thermal-time approach to the results. They find that base temperature for germination and thermal time requirement for 50 % germination explain the differences detected among populations. Modelling of the seed responses according to present climate conditions and two future predicted scenarios identifies an altitude-related risk from climate warming, with lowland populations being more threatened due to a compromised seed dormancy release and a narrowed seed germination window.