Think of this as a sequence of snapshots, each one caught in a few lines. The speaker moves through a city in summer, noticing sweat on a hand, a pigeon under a bus banner, a siren, an old man complimenting every young woman who passes. Nothing is explained. The poem simply lets odd, ordinary details pile up.
The mood is quiet, a little lonely, and often wry. The speaker reminds himself not to expect friendship, and the Fourth of July means nothing to him beyond "thick, rolling booms." Yet he keeps looking closely. Butterflies rise higher than a half-mast flag, chickadees settle for the night, and rotting trash becomes a beach at high tide if he chooses to imagine it so.
One line, "Every day is death, / every day is life," comes close to stating a theme, then admits there is little more to say. That honesty fits the whole piece: small attention, small consolations, and a sense that noticing is enough.