Many believe that the reason we have four seasons each year is because of Persephone. Demeter was so enraged when Hades took her beloved daughter Persephone, that she stopped going up to Mount Olympus and stayed on Earth and posed as a mortal. Because she was the Goddess of the Harvest, she swore she would never grow anything again and let it all die unless she got her daughter back.

According to the ancient Greeks, it is assumed that the spring and summer seasons are the times that Persephone was in the regular world with her mother. Then she spends fall and winter in the underworld with Hades. 

When Persephone is with her mother, Demeter is so happy and makes everything grow and look lucious. But when Persephone leaves to be in the underworld, Demeter just let's everything die. This corresponds to how we know the seasons: Spring is green into summer, and then things start to die in the fall and become dreary in the winter.