WATER or H20 has a blue tinge to it. you can not see this blue tinge when you only have a small amount of water but in large amounts a blue colour becomes apparent.
But water tends to reflect the colours of the stuff around it making it look multi coloured.
Anyhow you can see the colour of water easier when its in the form of ice. just get rid of the layer of frost around it first. then the blue colour becomes alot more easier to see.
Then if you still think its because of the sky, go into a room draw the curtains, put the light on then have another look







