“I wandered lonely as a cloud” consists of four six-line stanzas (or “sestets”), each of which rhymes ABABCC. Over the course of these four sestets, the speaker recounts how a chance encounter with a field of flowers has had a lasting influence on him. The speaker starts by describing how, while walking around feeling lonely, he came upon a patch of daffodils dancing in the breeze. In stanza 2, he recounts how he stopped to observe the flowers and consider their beauty. The speaker continues this account in stanza 3, where he compares the exquisite flowers to the sparkling water of the nearby lake. The speaker also notes being so enraptured by the daffodils that he felt fully immersed in the present moment. This observation prepares the way for the final stanza where the speaker shifts from the past to the present. He reflects on how, even when he is “in vacant or in pensive mood” (line 20), the memory of the daffodils brings a feeling of tranquility.

As the outline provided above indicates, the poem’s overall structure moves from the past to the present. Whereas the first three stanzas address the past event of the speaker’s encounter with the daffodils, the final stanza shifts to the speaker’s present. In a sense, the first three stanzas can be read as setting up the revelation that comes in the final stanza. This reading is supported by the way the speaker makes the transition from the third stanza to the fourth. Whereas the first two stanzas are both self-contained sentences that end with a full stop, the third stanza ends with a colon (lines 17–18):

I gazed—and gazed—but little thought
What wealth the show to me had brought

These lines set up an implied question, and they establish an expectation that the final stanza will answer it. The implied question is, essentially, What makes these daffodils so important? In the final stanza, the speaker answers this question by explaining that his memory of the daffodils provides him with a powerful, imaginative resource. It therefore isn’t the daffodils themselves that the speaker privileges. Rather, it’s the speaker’s own capacity to recollect a moment of such profound tranquility that’s most important.