And let's not forget also this image is a fine complement to Alain Briot's current article on Complementary Color Harmonies.
It would seem to me to be an excellent example of "Analagous Color Harmony", as opposed to "Triadic Color Harmony". 
But is it the "analagous color harmony" that
makes the picture?
For example, if you removed all of the grey clouds and had shades of yellow that became red, would that work?
It's hard for me to see how it would.
What makes the picture is that each component of it does its job excellently.
For example, the clouds gradually become darker as they are closer to the camera but the closest ones are red. By themselves the clouds are not a colour harmony as per the story because they're just the same "colour" but a different brightness until they completely change colour and become red. If you look at just the foreground with the farm, that too by itself works.
If you took away the contrast between the sky and clouds (for example) by making the sky darker then the photo would not work as well.
At least the impression that I get is that the colours that work well together to define a good photograph are related to each other by a much more complex relationship than has been presented thus far in this essay series.
