The poem begins with the line "Earth has not anything to show more fair," setting the stage for the description of the city's beauty. Wordsworth then goes on to describe the "bright" and "golden" buildings, the "smokeless air," and the "ships that, like a "fleet of swans," move gracefully on the Thames.
This specific time of day, the early morning, allows Wordsworth to see the city in a serene and uncluttered way. The lack of traffic and the absence of the usual hustle and bustle of London life allows him to appreciate the city's architecture and its harmonious relationship with nature. The calm and quiet of the dawn enhances the beauty of the scene and highlights the tranquility he sees.