The light yellow in the sky heralding the appearance of sun.
This is the color of sky to the west of the building. Here is the brighter yellow unlike the pale yellow on the right side.
With the Fall season the trees are shedding their green color. Yellows appeared first giving an illusion of sunlight, whereas the sun had long ago dipped into the horizon. In the mornings the same illusion persisted that the sun rays were trying to reach out, whereas the sky would be grey— no sun outside.