OK intuitively there is indirect and direct sunlight. Based on my highly unscientific personal experience I'd guess the body can tell between direct daylight and sunset spectra (both warm) and indirect daylight and twilight spectra (both cool). Electronic blue lights after lots of f.lux seem quite annoying, so I'd guess they are more like daylight.
Relatedly it always bugged me when I was little that blue lights seemed "white in the middle with turquoise then finally blue exterior". Blue lights just couldn't be both bright and saturated very easily. I wouldn't be surprised this is related to the daylight-ness vs twilight-ness.
Ah, all the better. So the day is neutral/cool or quite cool (direct or indirect) and the evening is warm or that twilight blue which https://www.flickr.com/photos/bob_81667/25663810348 is just the same indirect thing but darker?
Would seem like coolish is any time of day depending on brightness, but warm is definitely evening.
When the sun goes down, colour temperature is determined by the alternative light source. For most of the past 100,000 years, life on our rotating planet has relied on moonlight (cold) or firelight (warm) to see at night.
Incandescent lights (Edison light bulbs) are a bit cooler than the candles and (most of the) oil lamps they replaced.
Bright cold (high Kelvin rating) lighting at night is a very modern invention:
By "twilight" I meant the atmospheric scattering from the sun just over the horizon. Is that roughtly same color temperature as the "5,000 Horizon daylight"?
Relatedly it always bugged me when I was little that blue lights seemed "white in the middle with turquoise then finally blue exterior". Blue lights just couldn't be both bright and saturated very easily. I wouldn't be surprised this is related to the daylight-ness vs twilight-ness.