Well it gets much more colder down there. But nothing the Leghorns should be able to handle.
The only problem with the Leghorns is their combs, you have to watch for frost bite, but that is only really where it snows.
For a great layer I would go for Leghorns. They are the best purebred layers and mine go fine in the Australian Winter ( yes Im in Aus as well ).
You can also get them in many colours including - Exchequer, blue, blue-red, white, black, brown etc.
Look up Exchequers and blues, they are my...