How are the four seasons symbolic for Dexter in "Winter Dreams"?

It is clear from the title of this great short story and the way that seasons are referred to in the first section that the seasons are very important to the story and its theme. Note how the seasons are described and their impact on Dexter Fletcher:

Fall made him clinch his hands and tremble and repeat idiotic sentences to himself, and make brisk abrupt gestures of command to imaginary audiences and armies. October filled him with hope which November raised to a sort of ecstatic triumph, and in this mood the fleeting brilliant impressions of the summer at Sherry Island were ready grist to his mill.

Note how this shows that Dexter is sentimental, sensitive and romantic. The way that winter makes him "melancholy" and spring makes him "dismal" also hints that his "winter dreams" are doomed for failure in the coming of spring. Thus it is important to analyse the impact of the seasons on Dexter Fletcher and his "winter dreams," identifying the way that the coming of fall makes his dream seem more possible and spring strips away his hope.