Well, thanks for the brilliant and extensive reply! I will say that blue has been very weak (weather wise) this summer.

We have had a couple of periods (each lasting a couple of weeks) where the smoke from forest fires in Canada pretty much obscured the sky and just made it pale brown instead of blue. When that happens, the sea is also reflecting more gray than blue. Now we just got another session of very thick smoke from forest fires...

Interesting to see so much background on colors...