Source: The Great Interpretation of Dreams (Ibn Sirin)
Sunset in a dream indicates the end of a matter or the approach of one's end. It indicates the death of the sick or the dismissal of the ruler.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Sunset indicates the completion of work. It may indicate worry and grief.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Sunset is interpreted as worry. Whoever sees the sun setting will be afflicted with worry.