I don't know if this is still the case. There was a point in time where colleges and pro scouts preferred hard throwers from cold weather. The appeal was the odds of low mileage arms. With the development of so many indoor facilities I'm seeing cold weather kids toast their arms. So I don't know if the appeal still holds.
That was definitely the way they operated. However, I remember reading that once and wondered if there was any actual evidence to really support the notion or if it was just one of those things that made sense as a hypothetical.