Sun appears blue in midday because blue light with shorter wavelength scattered most. Agreed.
Sun appears red in sunrise and sunset because sunlight travels larger distance in atmosphere.
Then why cannot blue light scatter more during sunrise and sunset??
I can’t relate the reason for blue and red of sun as the concept behind them is different.
Asked Rahul Verma
Please see that during daytime SKY appears blue (not sun) because when we look at sky, it is the scattered light reaching our eyes and blue light (the blue region of the spectrum) is scattered the most and at sunrise and sunset the SUN appears reddish because the blue light is scattered and lost. The light coming directly from sun contains less amount of blue and the sun appears reddish.