A man walks along a sandy edge, a border of sorts, and blames the wind or clouds for how he feels. The poem quietly undercuts that excuse: his "seasonal allergies" are a convenient explanation for something deeper, a kind of alchemy that turns unease into a harmless physical complaint.
Back in his house, even the plastic flowers "couldn't keep time." They are meant to be permanent and unchanging, yet they can't hold off the passing of time, and they seem to mock the fake comfort they offer. The man stays restless, full of fears and uncertainties.
In the last stanza he builds "walls of alienation" around himself and is haunted by images of strangeness. The nude shade is hard to read, but it may suggest a vulnerable, exposed feeling. He survives, though only just, by enduring helplessness. The mood is uneasy, lonely and dry, with very little consolation.