A perfect summer's day calls for a perfect summer poem. No better than Shakespeare's famous sonnet 18 comparing his lover to a summer's day.
Maybe the two most infamous lines of poetry ever are to be found in this sonnet: Shall I compare thee to a summer’s day?/Thou art more lovely and more temperate' . They are also two of the most romantic I think. Who wouldn't beam at being compared to a summer's day, all bright and light and happy and uplifting?
But not only a comparison, the poet goes beyond and deems this person even better and more lovely than a summer's day. Summer fades and loses its beauty, but his lover is endowed of an 'eternal summer', his 'fairness' never wilts in the eys of the beloved. Now there's endearment for you!
*(Don't let the language trip you up! - you can read an explanatory line-by-line version of the poem here: http://www.shakespeares-sonnets.com/sonnet/18 )
Sonnet 18 - William Shakespeare
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 dimm'd;
And every fair from fair sometime declines,
By chance or nature’s changing course untrimm'd;
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.