Average temperatures or temperature ranges are often used as a simple proxy for climate. In combination with some description of rainfall, they encapsulate the essentials: in the Mediterranean it is typically hot and dry in summer and cooler and wetter in winter, and a continental climate is hot and dry in summer and cold with snow in winter, for example. But quantifying climate more precisely is fraught with difficulty.
Records kept over the years give us historical figures to make comparisons between average temperatures then and now. This sounds simple, but the very concept of an average temperature has no simple definition. First, we have to realise that temperature is what is known as an intensive property of matter. This simply means that it does not depend on the nature or size of the material for which it is measured.
So, for example, air and a body of water may have the same measured temperature at a particular moment, but their behaviour is very different.