Guessing your heat gauge is coming up to normal operating temps? If so, next step would be a simple check (grab hold of em) of the heater hoses going into firewall. If both are hot, water is circulating through heater core properly and a door inside the heater isn't opening/closing properly. Likely due to a vacuum leak.
If a large difference in hose temps, or both cool, then you could have a restricted heater core. Not that likely unless someone's allowed coolant system to become pond sludge.
Also, other than mild curiosity as to why it's so cold where you're at, couldn't give a flying fornication where your located.:happy175:
Bob