Judy,

succeeding Dexter's first exhilaration came restlessness and dissatisfaction. The helpless ecstasy of losing himself in her was opiate rather than tonic. It was fortunate for his work during the winter that those moments of ecstasy came infrequently.

Winter is physical removal from and a psychological escape or break from the diametrically opposite summer season.

Summer, on the other hand, represents immersion into the upper-class lifestyle. As a teenager, Dexter is surrounded by wealth and high society while working as a caddie at the golf club. As a young adult, he experiences his first affair with Judy during the summer at that same club. Now, though, he is there as a guest of a member, not as an employee. Just before he spots Judy, he notices

Later in the afternoon the sun went down with a riotous swirl of gold and varying blues and scarlets, and left the dry, rustling night of Western summer.

The intoxicating moonlight, gentle waves on the lake, jumping fish, swimming, and boating all represent a dreamy, romantic leisure class that Dexter has not fully entered but is only visiting. While dining with Judy at her summer home, he feels he has almost attained what he dreams for during the winter: admission to the carefree, affluent high society.

Unlike winter and summer, however, autumn and spring are transitional periods when Dexter’s moods shift from depression to hope and then back to depression. He holds a different attitude toward each transitional season. During the fall, he feels potentiality—perhaps being fresh from positive summer experiences—before entering hopelessness and painfully aspirational dreams in the winter. When Dexter was a boy,

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.

Autumn is when his dreams are filled with optimistic possibility before becoming taunting objects of longing during the winter. The fall after his first summer with Judy, Dexter happily learns that she grows bored with son of trust company owner visiting her during September. Ironically, while the leaves are dying, Dexter’s hopes are thriving.

Spring symbolizes Dexter’s painful realization of his winter dreams—the season teases him with the dreams’s potentiality, yet mock how far removed he is from attaining them. As a boy, he notes the abrupt transition from winter to summer with the observation that

there was something dismal about this Northern spring, just as he knew there was something gorgeous about the fall

During college, he hears piano music (later played at the golf club when he reconnects with Judy) wafting from an out-of-reach dance “when he could not afford the luxury of proms, and he had stood outside the gymnasium and listened.”

Dexter’s hopeless courtship of Judy is represented by the seasonal calendar:

Summer, fall, winter, spring, another summer, another fall—so much he had given of his active life to the incorrigible lips of Judy Jones.

The second autumn is when Dexter finally realizes she is not interested in him beyond a superficial fling. This season is also when Dexter decides to change the course of his life. In October he and Irene meet; by January, they are engaged to marry that summer. So interestingly, now winter and spring briefly symbolize hope, rather than harshness and anxious longing, for Dexter.

The Minnesota winter prolonged itself interminably, and it was almost May when the winds came soft and the snow ran down into Black Bear Lake at last. For the first time in over a year Dexter was enjoying a certain tranquility of spirit.

Quickly, however, spring returns to a negative, dangerous time. That spring, Dexter runs into Judy at the University club and they resume their affair. Although Irene and her parents break off the engagement and Judy ultimately rejects him, he does not regret their reconnection.

The following year,

He went East in February with the intention of selling out his laundries and settling in New York—but the war came to America in March and changed his plans. He returned to the West, handed over the management of the business to his partner, and went into the first officers' training-camp in late April. He was one of those young thousands who greeted the war with a certain amount of relief, welcoming the liberation from webs of tangled emotion.

Dexter again changes the course of his life and goals. Finally, winter and spring become seasons of potential, hope, and freedom.

Consider also the idea that  seasons are often symbolic for the life cycle---spring is our youth, summer is our young adulthood, autumn is our mature years, and winter is a time of old age.

Now see how Judy herself is associated with each of these seasons and the time period in Dexter's life.

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.