Temperature compensation is easier. There is a temperature coefficient for each buffer, defining the change in pKa that ensues for every degree (dpKa/dT). These coefficients are usually provided at 25°C. Many buffers, especially Tris, have high temperature coefficients (e.g., for Tris it is -0.028/°C). Buffers with high coefficients change their pH dramatically with temperature.
The BufferStack will calculate the pH to which a buffer should be adjusted at one temperature (usually the lab temperature) in order to yield the correct pH and ionic strength at a different temperature.