Method
Daily Minimum Temperature in July
Both low and high night-time temperatures in winter can limit fruit crop productive potential. Very early flowering stone fruit cultivars can develop chilling injury to buds when temperatures are very low during flowering, while hot nights in this period can potentially damage pollination processes. Both conditions can lead to low fruit set. An extended period of very warm winter nights can interfere with the normal accumulation of chill units and result in trees not reaching the dormant state before spring, as well as triggering early flowering. High night-time temperatures increase respiration rates of emerging leaves and create a carbon deficit in the early growth stage.
The mean monthly night-time minimum temperature (Tmin) in mid-winter (July) 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).
Maps
Map Information
The Klein Karoo (East) has a historical Tmin (July) of 4-7°C (regional average). Climate model projections for the intermediate future (mid-century) show an increase of around 2.0-2.2°C (higher values in the eastern areas).