Why does the Moon sometimes look Yellow? My friend and I both noticed that the Moon looked yellow Yesterday, but it wasn't like that the same time the day before, as far as I remember. 

Does the Moon sometimes look Yellow? If it does, why does it?
Because light with higher frequency, that is bluer colors, scatters more in Earth's atmosphere and celestial objects thus look redder (yellow is towards red) while the atmosphere looks blue. See Rayleigh scattering. 
Here is video with a lengthy and somewhat entertaining explanation:
https://www.youtube.com/watch?v=SRh75B5iotI