Santa Claus used to be green and a grumpy fellow till the 1920s before a certain Coca-Cola ad campaign.
This is how people perceived Santa before the 1920s:
How Santa looked in the ad campaign:
So now we know this cheerful guy is always in the red suit.
It was just one little known story about how manufacturers change the world.
Merry Christmas and a successful 2016 year!
Information from Quora and Coca-Cola company