Summer (Symbol)
Summer is referenced right at the beginning of the poem, but is eventually developed into a character at the poem's conclusion. The speaker refers to summer as a beloved guest about to make "her" departure from an event. This characterization neatly encapsulates much of the poem's earlier ideas. Summer becomes the ideal model for a season that passes by without notice and is missed immediately. Dickinson personifies summer because it gives it a more meaningful and concrete symbolic presence in the poem. This choice literalizes summer and the emotional associations it carries with it. Summer becomes a stand-in for moments that people want to hold onto, even as they slip away. It is a particularly strong choice as a seasonal image, as its disappearance is felt pointedly on the first cold day of fall.
Keel (Symbol)
Dickinson employs the nautical image of a keel to highlight certain aspects of summer's character. A keel is a structure on the bottom of a boat that helps steady it in the water. The additional weight it provides keeps the boat more centered, particularly in choppy seas. The speaker states that summer does not need the aid of a "keel" while "she" is making her exit. This small reference symbolizes the subtlety of summer's exit. As the poem has explored extensively, time (particularly in relation to days and seasons) passes with no notice. Summer's lack of a keel emphasizes the understated quality of its exit. It requires no help with stability or centering.
Time (Motif)
The poem's central motif is time. Through descriptions of days and seasons (specifically, summer), Dickinson returns to time again and again in the text. The poem's main thesis about time is that while its passage occurs unobserved, its effects are strongly felt. This is apparent from the very first lines, in which summer's end is compared to the progression of grief. Time's progress is shown to be something primarily experienced and not seen, much like the quiet transition from day to night or from summer to autumn. Time is perceived only when it causes absence and loss, as we see in the speaker's disappointment about the close of summer. In the speaker's analysis, time moves imperceptibly but its reverberations are felt immediately when it causes a change (day to night, summer to fall) in the outside world.
