Singapore, New Zealand, Chile, Canada, etc..
Australia is a better choice than EU 
Able to continue my study in a different country. Couple of months left to decide. What would be best in the long run? Undergrad applied mathematics.
Canada would in theory allow you to more readily integrate with work opportunities in Canada or USA. Australia would in theory allow you to more readily participate in the boom coming in Asia from 2020 onward. I would think both have good universities. Australia is less cold. Consider cultural differences, even within different cities in the same country.
Definitely.
Different cities in Canada are hugely different in terms of cold. Vancouver is hardly cold at all (by comparison, Calgary is extremely cold) and is closer to Asia than other major cities in Canada (closer to Beijing than Melbourne for example). Also has strong cultural ties with Asia after decades of immigration.
I'm less familiar with Australian cities, but I would guess some of the same.