Night after night, the speaker watches the sunset shift while the rooftops beneath it stay exactly as they were. Everything around them seems to move on, or decay, yet nothing responds to them. The trees drop leaves onto the concrete, and the speaker feels they would age more quickly than the speaker does, which suggests a sense of being stuck in time.
The heart of the poem is a longing to be heard. The speaker imagines shouting at the rooftops that they care, shouting until their voice gives out. The line about guilt is striking: the rooftops don't care whether the speaker is guilty or innocent, so there is no judgment and no forgiveness either. Even the scream, the poem says, brings only its own absence, an emptiness afterward.
The mood is lonely, tired, and quietly desperate. The repetition of "every night" and "the same rooftops" makes the days feel like a loop, and the ending offers no escape from it.