In their native habitat or at a standardized temperature?
I'm Scandinavian, and I'm comfy and dry when I can wake up seeing my own breath. After moving to California, though, I'm pretty sure I'm single handedly ending the drought.
Excessive sweating is probably a disease rather than race-related. In Chinese traditional medicine it is called 虚汗, so it definitely can affect at least one more race than Irish.
I'm basically Irish, and boy do I sweat. Even when I was young and fit, I would be drenched when my co-workers/friends looked dry.
My brother once asked the family doctor about his sweating. The doc just said everyone is different.