The volta shifts from the discussion of why a summers day would be a poor comparison to the beloved's 'eternal summer' The Fair Youth will be at the height of his beauty forever. The progression of verbs in this sonnet-shines, dimmed, declines, fade-reflects the passage of time. However, it could equally be seen as a gardening metaphor whereby plants go to seed or become unkempt from time to time. Thus the 'rough winds' in line 3 are reiterated, once again representing the unrelenting forces of nature. The use of 'untrimm'd' draws on a nautical metaphor: the adjustment, or trimming, of sails to fight the direction of the wind.

Fairness fades as a result of both accidental decay as well as 'nature's changing course'-in other words, aging. The line tells of the inevitable fading of physical beauty: on the surface, fair people will lose their fairness. In its second instance, 'fair' is used in its typical form as an adjective. The first 'fair' means 'one who is fair,' or beautiful. Personification of this eye enhances the fair youth of the poem as a whole, for dimming his gold complexion implies hiding the beauty of the individual whom the poet addresses-something the poet intends to prevent for the beloved. The use of metonymy in 'eye of heaven' (the sun) illustrates the power of that device: The eye is usually thought of as the agency for perception and character here the central focus of the sky seems central to the concept of nature itself.

The speaker uses the metaphor of summer's lease being too short, aptly indicating the transitory nature of a season and, by extension, a year and a life. His use of the term 'darling' extends the harmonious concept to include the vision of an orderly universe embracing its creations and processes with affection. This objection might seem trivial until one remembers that the poet is invoking a sense of the harmony implicit in classical concepts of order and form which writers of the Renaissance emulated. His first criticism of summer is that in May rough winds shake the 'darling' buds. He is unconfined by the changing of the seasons. It means both having a calm and even temperament, and 'a period of time.' This description of the youth embodies not only his perfect character, but the ability of this perfection to outlast time.

This fourteen-line poem begins with a straightforward question in the first person, addressed to the object of the speaker's attention: 'Shall I compare thee to a summer's day?' William Shakespeare develops the 'temperate' elements of his comparison first, leaving the 'lovely' qualities for later consideration.

Sonnet 18 iambic pentameter analysis