Our idea of "warm" colors is just a historical accident. Wood burns orange because it produces soot, which glows orange in the flame. Same applies to candles too, because there’s never enough oxygen to burn all the carbon.
If we’d started with purified hydrocarbons instead, blue might have been the ultimate "warm" color. Natural gas burns with a blue or even invisible flame, a sign of complete combustion. Orange, then, would be the color of flawed, struggling fire.
Imagine a house heated and lit by a gas furnace instead of a traditional fireplace. The light from the fire would be blue, and we’d associate that glow with warmth and coziness. Picture old paintings with a cozy atmosphere, their hearths glowing blue. If everyone grew up like that, blue would be the warmest color instead of orange.
"Different flame types of a Bunsen burner depend on oxygen supply. On the left a rich fuel with no premixed oxygen produces a yellow sooty diffusion flame; on the right a lean fully oxygen premixed flame produces no soot and the flame color is produced by molecular radicals, especially CH and C2 band emission."
Source: Wikipedia
The sun is, by definition, white. White is what we call it when an object reflects all spectra of sunlight.
It's only at sunrise / sunset when the atmosphere filters out more of the blue spectrum that it apparently turns more orange/red.
White light is light that contains all visible wavelengths at the roughly the same proportions. The sun has nothing to do with this definition.
Our sun is actually slightly greenish-blue as that is where it's peak (visible) output is.
The key word there is "visible". Our eyes adapted to the spectra of our star when filtered by our atmosphere. We perceive that spectra as white.
Our perception is limited and our understanding has long outgrown it. White light, by definition is all visible light at equal intensity, thus the sun is NOT white.
Use RGB codes for example. White, by definition would be 255, 255, 255.
The Sun is more like 245, 253, 255 or something .... still looks white enough to us, but by definition, isn't.
Can we agree it's not orange? That is what I was originally pointing out.
From a physical standpoint, sure.
But I'm pretty sure that if you casually ask most people which colour the sun is, you'll hear yellow/orange much more often than white. So for the context of which colour was, prehistorically, associated with warmth I think yellow/orange are the more relevant answers.
Actually...
our eyes adapted way back when our ancestors were fish. So we see light in the range that light passes best under water.