The song unfolds as a contemplative ballad, infused with a sense of nostalgia and lingering affection. As the protagonist reminisces about the good times shared with their former lover, the lyrics paint vivid images of their shared experiences and the impact of the breakup on both parties involved.
The recurring line throughout the song, "I still hear your voice in the morning sun and I still see your face in the afternoon sun," signifies that the narrator carries the presence of their ex-partner with them, even as time passes. The imagery of the morning and afternoon sun suggests the constant presence of memories, both good and painful.
The song builds to a poignant climax as Daughtry sings, "I will lay down my life to remember the thrill that you gave me." This line expresses a bittersweet longing for the excitement and passion that marked the relationship. However, the chorus that follows introduces a mix of hope and regret: "In the month of September, it never felt so cold, but I feel your body warm every night I hold." Here, the singer finds solace in the lingering memories and the warmth they bring, even amid the emotional chill of the end of the relationship.
Overall, "September" captures the essence of longing and reminiscence, conveying the struggle to move on after a significant loss while still holding onto the fond moments of the past. The song's reflective tone and emotional depth resonated with listeners, contributing to its success and relatability.