AP English Literatur

What poem is 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. -Sonnet 18