It is just what you get used to. Before moving to Florida, I lived in Phoenix, AZ for 8 years. I got to where I quite enjoyed being able to wear t-shirt and shorts while putting up outdoor Christmas lights. Made it fun for me. If it was cold, I don't think that I would have done half the outdoor decorating that I did.
I think that everyone finds their own way to get into the holiday spirit regardless of where they live. Every region will cue off of different things. In the warm climates, I start finding the spirit when the decorations start going up in the neighborhoods. I don't miss the "winter" weather and don't need it to get into the Christmas spirit.