Fruit crops have critical lower temperature limits for growth and fruit quality. An air temperature < 6°C can have both positive impacts (e.g. induction of synthesis of red pigment in red fruit) and negative impacts (e.g. disruption of chilling accumulation; disruption of pollination, fruit set and growth processes; changes in pests and diseases). At temperatures ≤ 0°C, frost risk increases.
The number of days per annum when the minimum air temperature is below 6°C was calculated from daily temperature data. More detail is provided in the section Background: Climate Change Modelling.
The modelling for the intermediate future (2050s) was conducted using five different CMIP3 GCMs (Schulze, 2011).