Maybe, but there are a lot of other possibilities. A more common one would be if your car’s thermostat is opening too soon, so the engine isn’t running hot enough. That’ll reduce the heat to the passenger compartment.
Even worse, it can cause your car’s engine to run inefficiently, wasting gas and increasing emissions.
Of course there are other possibilities, including a clogged heater core. The best way to be sure what’s wrong is to take your car to your local Cottman center. Their technicians will be able to check the car’s cooling and heating system, and let you know what it’ll take to get the passenger compartment nice and toasty on those icy winter days.