I think this is about Morrissey relating his boring, sad and depressing existence (and in life in general) through relating it to a wet, seaside town on a Sunday. Bearing in mind it was the late 80s when there wasn't much open or to do on a Sunday anywhere let alone a seaside town out of season in Britain. I think he just describes a powerful scene of a lonely seaside town as an example which we relate to. This is typical of him in many of his and the Smiths songs to describe things we can relate to as a means to portray a point.
I think this is about Morrissey relating his boring, sad and depressing existence (and in life in general) through relating it to a wet, seaside town on a Sunday. Bearing in mind it was the late 80s when there wasn't much open or to do on a Sunday anywhere let alone a seaside town out of season in Britain. I think he just describes a powerful scene of a lonely seaside town as an example which we relate to. This is typical of him in many of his and the Smiths songs to describe things we can relate to as a means to portray a point.