Even the likes of Harbaugh at Michigan and Urban Meyer have commented that recruiting to northern climate schools is much more challenging, particularly for elite skill player kids. Not sure how anyone can dispute that. Coach Prime recently said that the weather is the biggest challenge with getting kids to Colorado.
It's not an excuse, and good coaches can overcome it by bringing in tougher kids. If they choose schools based on warm weather, odds are those same kids will fold their tents when the going gets tough; but let's not dismiss the reality that really fast players prefer warm weather.