There may be some correlation to that... but personally, I think weather/climate has a lot to do with the development of athletes.
It's a lot easier to go to a gym in the winter and shoot hoops than play pick-up football with your buddies in 7 inches of snow.
Same thing for baseball. In the south, we can play year round (almost). In the north, between November and February, it's tough to play because of the weather.
Don't forget that we train (in the south) during some brutal months to be outdoors (July, August). I think going through that adversity helps in a similar fashion that training for a marathon in high altitude does.