Shown above is a phenomenal gold and vermilion sunset as observed from Tucson, Arizona or November 14, 2014. The best colors are rendered when either mid-level clouds occupy the western sky at sundown, as in this case, or in the absence of clouds when aerosols , from wildfires or a volcanic eruption for example, are prevalent in the atmosphere. Here altocumulus clouds were positioned just right to catch the Sun's lingering rays.