shades of blue

Oooh! There a lot of variables in that one. Where do I start? The proximity to a large body of water can influence "blueness". I'm thinking it's also due to the exact mixture of atmospheric gases & the presence or absence of contaminants like dust particles as well as other gases generated by industry & agriculture. Temperature up there can also play a part, albeit a small part. Well, these explainations used to be commonly accepted, but since Sir Isaac Newton's experiments & others besides, the story has changed. Try looking up pages like this: http://www.math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html

I think its cool how anywhere you go, you know you are under the same sky yet it can look so different.

I think it has something to do with how the sunlight reaches the atmosphere, the angle. It may also be dew to the humidity of the air in that area. I think there are a lot of factors here but I guess the more important one is the way sunlight reaches that are. I'm not sure tho, it's just a hunch.