I don't think it has so much to do with climate as it does with upbringing. I think if a person is from a small town and had a rural up bringing that they will take that up brining with them wherever they go. If a person grows up in the hustle and bustle of a big city, that forms a part of their personality and they take that with them as well. I am a 4th generation native Floridian. I grew up a beach bum if you will and still carry that laid back kind of way of being with me. My husband is from the Caribbean, but he is from the capitol city where the majority of the people on the island live. He moved to New York City when he came to the US and even though the weather was a bit of a shock, he wound up falling right into city life without missing hardly a beat.
I find Floridians to be generally pleasant and laid back people, but down here we have a myriad of people from other states and countries. As I come across them in my day to day life, I would wager to say that they are pretty much the same as they were in their home state/country as they are living here now, with the exception of adjusting to the climate and culture here. I find the "big city people" still have a big city attitude and way of being and people from other countries still maintain their customs as much as they can here.
I know for my own family, being Spanish and Cuban, they maintained their culture and language very well here even in spite of living here for so long. We all grew up speaking Spanish and I know all of my family's stories all the way back to The Old Country.
That's been my experience for what it's worth.