[misha1967]

A slight addendum to the above:

I saved and exited to post the post above, and when I reloaded, the "fluffies" were back but, and this is the important bit, the sky behind them and between them was still blue, the way it's supposed to be.

The "fluffies" which are, obviously, something built into the 3D clouds in the stock game meaning they'll be there even with "skies clear" weather reports are actually quite realistic. In that particular climate zone, and I speak as one who grew up there, completely clear skies without as much as a hint of "fluffies" is extremely rare and, besides, they look good as opposed to the 2D alternative.

But the ONLY time that the sky between the fluffies is the white/grey with perhaps a hint of blue in there is when the fog level is above "all clear", and that seems to be the problem here. Yes, even fog levels of, in sim terms, "1" will haze over the blue and make it whitish/grey, but when the fog is zero whatever you can see of the sky is a beautiful blue.

And apparently that changes in the sim when you shift from "day" to "dusk" into "night" and "dawn" and then turns whitish grey when you go back to "day".

It all has to do with the angle of the sun as defined in the EnvColor files, I'm sure.