Painting sunset in watercolor requires a lot of pre-thinking and yet when painting it needs to be done quickly before the paint dries. The technique I used for the sky was wet-on-wet.
I watched carefully that the Sun’s area stayed reserved and the sun rays were “melting” into the evening sky. One who paints sunset in watercolor needs to remember that the yellow of the sun and the blue of the sky might get a slight shade of green when mixed together on the paper. Therefore, it is important to add a little of pink towards the edges of the green. It is invisible on the completed watercolor painting but it is there.. it melts with the blue of the mountains and the sky and helps atmospheric perspective to take place.