Explanation: Just to elaborate a little on the answer, it can be added that the tone in this famous and beautiful sonnet (one of the more than a hundred that he wrote) is clearly romantic, since the speaker is praising the beloved one, establishing a comparison between him and the summer. The beloved one is, nevertheless, superior, "more lovely and temperate," and his beauty does not perish ("But thy eternal summer shall not fade / Nor lose possession of that fair thou ow’st [...]"), since it will always be preserved in this poem ("When in eternal lines to Time thou grow’st [...]").
On the other side of the island, "swathed at midday with mirage, defended by the shield of the quiet lagoon, one might dream of rescue," but, on this side, "the brute obtuseness of the ocean" makes rescue seem impossible.
