system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Especially in the winter when there's snow on the ground, why does everything have a blue hue to it just before sunrise and sunset?
gpt
Light diffuses (understand deviated) when propagating in the air. How much it diffuses depends on the wavelength (its color).

The sun emits a wide array or wavelength, and its "blue rays" are among the most disrupted by air. That is why the sky by day is blue. They are so much deviated that they look like coming from where the sun is not, giving the sky its opaque blue look. (Imagine air particles acting like tiny mirrors in random directions, reflecting only blue light)

Now imagine the sun being slightly beyond horizon. Rays that makes the light look "white" are for the most part not reaching you. Except blue ones.  
As they are redirected by diffraction, they reach places the other ones do not have a direct path yet/anymore. That is why before dawn/after dusk everything is blue-ish. (Snow only makes it more noticeable because it's white.)