Method
Mean Annual Temperature
Mean annual temperature (MAT, in °C) represents the very broadest of indices of the environmental status of a location. Although it integrates and smooths the effects of diurnal, monthly and seasonal patterns of maximum and minimum temperatures, it is nevertheless used as a general first guide to determine the suitability of a location for specific crops.
MAT was calculated from daily temperatures. 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 Breede Valley has a historical MAT of 16-17°C (Nuy, McGregor) and 17-18°C (Worcester, Robertson, Bonnievale). Climate model projections for the intermediate future (mid-century) show an increase of generally 2.2°C across the valley.