While those gorgeous, vibrant hues or a mackerel sky can look absolutely stunning in colour, they are much less effective in black & white.
That brief period before sunrise and after sunset when the sky can be a palette of beautiful colours is a must for the camera, but perhaps not in mono. While those gorgeous, vibrant hues or a mackerel sky can look absolutely stunning in colour, they are much less effective in black & white. A bold foreground in silhouette might work, though.