What is an example of personification in Sonnet 18?

I can add a couple more examples to the previous answers if it will help.

Of course the entire sonnet creates the idea that all the elements of nature share human characteristics which can be compared to the speaker's love. To the examples already discussed I can add some less literal examples.

In line 2, the speaker uses the word "temperate." While this word does refer to the climate of a region, it also can define a personality type that features restraint and moderation, belonging to a person who is not prone to tantrums, violence, or even unexpected mood swings. Here, the speaker is suggesting that his love is less extreme than the summer day, which may switch quickly between mild mornings, extremely hot afternoon temperatures and violent evening storms. This word is an interesting one which can refer to climate or to an individual.

In line 4, the speaker references "summer's lease" to refer to the duration of time that summer exists. The term "lease" is a human concept which indicates an amount of time that a person may occupy a house, apartment, or even a car. The speaker is making the comment that summer does not stay all year, but his true love will be in his life all year long and forever.

Personification is the attribution of human characteristics to things that are non-human. In this sonnet, we see the personification of natural forces.

The use of the adjective 'darling' to describe the plants in May is an example of personification. This kind of adjective is more usually applied to people. Even the image of the 'rough winds' that shake the plants could be regarded as personification to a degree, as it comes across rather as though the winds are deliberately shaking the plants, as a person might.

An obvious example of personification is that of the sun, referred to obliquely as 'the eye of heaven' and said to have a 'gold complexion'. Also, personification here is evident with the use of the word 'his', instead of 'its'.

Death, an abstract noun, is also personified here with the use of 'his', and the image of death 'bragging' about claiming the life of the beloved.

The sonnet itself 'lives', according to the poet, as though it were a person.

Overall, we may observe that the season of summer is also being personified in a way, as it is invoked as a point of comparison with the poet's beloved.

The sonnet goes like this:

Shall I compare thee to a summer's day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date:
Sometime too hot the eye of heaven shines,
And often is his gold complexion dimmed,
And every fair from fair sometime declines,
By chance, or nature's changing course untrimmed:
But thy eternal summer shall not fade,
Nor lose possession of that fair thou ow'st,
Nor shall death brag thou wander'st in his shade,
When in eternal lines to time thou grow'st,
So long as men can breathe, or eyes can see,
So long lives this, and this gives life to thee.

The idea of the sun having a "gold complexion" (line 6) is personification, as is the idea that death can brag about the reader wandering in his shade (line 11).  In addition, the final line, referring to the sonnet having life is also personification.

A metaphor is a comparison that does not use the words "like" or "as." The overarching metaphor in this sonnet is that the speaker's beloved is better than the summer's day they are compared to. In likening the beloved to a summer's day in this novel way, in which the metaphor emphasizes differences rather than samenesses, the speaker is taking a fresh look at the worn-out cliché of comparing a lover to summer's beauties.

A specific metaphor or comparison within the extended metaphor of the beloved as superior to summer is the following:

Sometime too hot the eye of heaven shines

In other words, the comparison of the beloved to a summer's day shows the beloved as better because sometimes the sun (the "eye of heaven") is too hot. This, implicitly, is never the case with the lover.

Likewise, the speaker notes that:

often is his gold complexion dimm'd

In this comparison, the personified sun is shown when he is hidden behind a cloud: summer days are not always beautiful, as the lover always is.

Further, the speaker states:

every fair from fair sometime declines,
By chance or nature’s changing course untrimm'd;

The basic notion in Sonnet 18 is that the beloved cannot legitimately be compared to any features of the natural world, no matter how beautiful they may be. This is because the real beauty of the speaker's beloved cannot be captured in the here and now, in a world of constant change, but only in the immortal lines that Shakespeare has deigned to write about them. In that sense, thanks to the wonders of art, the beloved is able to transcend the everyday world in which we all live and which is subject to the ever-changing seasons.

Toward the end of the poem, the speaker alludes to the old horticultural practice of grafting, whereby the branches of one plant would be grafted onto the body of another, thus giving the branches a chance to live on.

When in eternal lines to time thou grow'st

In effect, what Shakespeare is doing here is to "graft" his beloved onto time and, by doing so, allow the beloved to live forever, immortalized in verse. Like all the various features of the natural world, the speaker's beloved will eventually decay and die. But having been grafted onto time by Shakespeare's unforgettable words, they will live on in the poem as it is read, enjoyed, and analyzed by successive generations.

What is the importance of personification in the development of Sonnet 18?

Personification plays a very important part in the development of this famous sonnet in the way that it allows the speaker to personify both the sun and death as he develops his argument as to why comparing his beloved to a "summer's day" would actually be a very inadequate and inaccurate comparison to make.

Firstly, the sun is personified as the speaker talks about its many imperfections:

Sometime too hot the eye of heaven shines,
And often is his gold complexion dimm'd...

The sun is personified as a face which helps explain the way in which the "eye" of the sun can shine to hotly or its "gold complexion" can sometimes not be as bright and shiny as we would expect it to be. Personifying the sun helps the speaker develop the way in which the sun's imperfections make it an inadequate point of comparison for the beauty of his beloved.

In the same way, death is personified in the following quote:

Nor shall Death brag thou wander'st in his shade,
When in eternal lines to time thou growest...

As the capital letter and context illustrates, Death is personified as a man who boasts about the way in which everybody has to come near to him and finally confront him as they age and finally die. The speaker says that this poem will prevent this from happening as he is effectively capturing the beauty of his beloved and keeping it enshrined for all eternity away from the corrupting power of death and aging.

In Sonnet 18's third line, what is personified?

The speaker personifies wind in the third line of “Sonnet 18.”

Often referred to by its first line as “Shall I Compare Thee to a Summer’s Day,” Shakespeare’s “Sonnet 18” compares a woman to a summer day.  Like a summer day, a woman’s beauty is not necessarily going to last.

Personification is describing something nonhuman with a human quality.  In this case, the wind is described as being “rough” in the way that a person would, intentionally shaking the delicate buds.

Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date: (lines 3-4)

Too soon, the summer’s day with end, just as a woman’s youth will.  Each is beautiful and wonderful, and worthy of celebration.  However, part of the reason is the fact that neither will last.  We appreciate them for the brief time we have them.

Personification allows Shakespeare to add emotion to the poem.  The image of a mean wind messing with the helpless flowers will stick in our heads, and we will feel sorry that neither the summer day nor the woman's youth can last forever.