It is interesting to see that the customs and traditions that most Argentines have today are connected to the country's past!
The tradition of drinking mate is connected to the climate here in Argentina. Argentina gets very cold in the winter, typically when most North Americans would have their summers. Winter hits around May, June and July, during which time the heat can drop to temperatures as low as 10 degrees Fahrenheit. Most mate is served piping hot, and I think that is because it is a way for the Argentine people to stay warm during the winter. Since the drinking of mate was very popular among the Argentine gauchos who lived year round in the Patagonian grasslands, where it usually cold and dry, it makes sense that the beverage is served really hot. Of course, even when it is warm outside, Argentines still drink hot mate!