By definition, contrast is (to put it very simply) to be different especially in a way that is very obvious. It also means the differences of light and dark in adjacent areas, as well as in personality, experience, taste, and other areas. Contrast is not always obvious, but subtle and delicate, something for which you must search.
As we move into autumn, the seasonal contrasts become marked with a shift in the lighting, the later sunrises and earlier sunsets, and the cooling of the nights. In California it is far more subtle than what I recall from my childhood time in the midwest and New England.
These little changes make me so restless. While flocks of Canadian geese do not fly overhead here, adding to the melancholy of dying summer, the cooler weather, the desire to be outdoors to play, and be indoors to read or knit, make going to work not something I want to do! I’d rather see what is going on outside!