Symbolism of Shakespeare - Summers Day - Sonnet 18

Shakespeare’s Sonnet 18, beginning ‘Shall I compare thee to a summer’s day?’ is one of the best-known poems in all of English literature. The poem is often viewed as a love lyric, but can alternatively be interpreted as a poem about the power of poetry to immortalise the human subject of the poem.
However we interpret Sonnet 18, it’s clear that the poem succeeds in part because of the strength of its symbolism, so let’s take a closer look at some of the key symbols in Shakespeare’s poem.

Sonnet 18: addressee
Before we come to the symbolism, it’s worth bearing in mind that this poem is actually written to a young man rather than to a woman. Shakespeare is addressing a fair-haired young nobleman – usually known as the ‘Fair Youth’ – and singing his praises.
This is probably because he was commissioned to write some poems for the young man: one conjecture has it that the young man didn’t intend to marry and sire children; his father, keen to change his son’s mind, enlisted the help of the youth’s favourite poet, Shakespeare, and commissioned him to write poems which would open the young man’s eyes to the virtues of matrimony and fatherhood.
Whatever the true genesis of Sonnet 18, the fact remains that the poem was written to honour the beauty of a young man, the so-called ‘Fair Youth’.
Summer.
The most explicit symbolism in Shakespeare’s poem is found in that image we encounter in the opening line of the poem: the comparison between the Fair Youth and a summer’s day.
Summer has connotations of beauty, warmth, and happiness: sunny weather, the flowers and trees all in bloom, the skies clear. But for Shakespeare, the Fair Youth is more beautiful, and more ‘temperate’ (that is, mild or pleasantly warm in nature) than a summer’s day. After all, sometimes you get rough winds in summertime, and sometimes it’s too hot to be pleasant, so summer has its drawbacks.
Shakespeare draws on the pleasant connotations of summer but then focuses on the negative aspects associated with the summer season to ‘prove’ that the young man is better.
However, note how the difference between the Fair Youth and the summer’s day is collapsed by the time we get to the ninth line: ‘But thy eternal summer shall not fade’. Now the young man is the summer, absorbing all of the best qualities of that season (warmth, beauty) but none of the downsides (summer is over too quickly, whereas the young man enjoys an eternal summer).
But there’s something else too: when summer is used in relation to a human lifespan, it symbolises the prime of one’s life. In other words, the summer is your peak years, where you have attained adulthood, flourished, and grown, and you enjoy the full ‘bloom’ of your life. And as Sonnet 18 develops, it is this quality of the summertime – the idea of being in the prime of one’s life – that becomes more relevant to what Shakespeare is saying about the young man.
Day and Daytime.
Allied to the symbolism of the summer as a time when one is in one’s prime is the choice of daytime: it is a summer’s day, specifically, rather than a summer morning or a summer’s eve, for instance, much less a summer’s night. Shakespeare wants to draw on all of the strong connotations of the day: the warmth of that summer heat, the sun being high in the sky, the day having got going but not yet winding down.
Indeed, Don Paterson, in his entertaining and informative guide to the Sonnets, Reading Shakespeare’s Sonnets: A New Commentary, recommends that readers of Sonnet 18 place the emphasis on ‘day’ rather than ‘Shall’ in that opening line, so ‘Shall I compare thee to a summer’s day?’ rather than ‘Shall I compare thee to a summer’s day?’
After all, the poet’s question is mere rhetorical sleight-of-hand: he isn’t asking the youth’s permission, or wondering whether he should go ahead and make the comparison. He intends to do so, and the important information in the line comes at the end, with the double height of ‘summer’ and ‘day’.
Death.
In Sonnet 18, Shakespeare personifies death as a figure comparable to the Grim Reaper: a figure in whose shadow or ‘shade’ the Fair Youth would otherwise walk in, were it not for the Fair Youth’s death-cheating abilities.
Rather than being doomed to follow where Death leads – as all mortal beings are – the Fair Youth, through being immortal and having an unending ‘summer’, will never have to worry about falling into the dark shadow of Death.
The Poem Itself.
Perhaps the most important symbol in Sonnet 18 is Sonnet 18 itself: the poem is a symbol in its own right, because it symbolises the poet’s belief in the power of his words to overcome death and make the subject of the poem immortal.
The concluding couplet to Sonnet 18 becomes even more significant, then, when we analyse it in the context of the sonnet sequence as a whole: the previous seventeen sonnets have all made the argument that the Fair Youth can become ‘immortal’ by getting married and siring an heir, and thus allowing his family ‘line’ to continue.
Now, however, it is Shakespeare’s ‘lines’ – the lines of verse he writes – which will guarantee the young man immortality of a kind.