What happens if you let the car idle for a good, long while....say 30 minutes? If the temperature never goes above 82C, then I would suspect that the thermostat is "stuck" open. But if you are driving short distances in cold weather (you mentioned that it had recently begun snowing), it is entirely possible that the engine is just not getting warm enough to register the temperatures you expect to see on your gauge. Highway driving at a steady rate is easy on the engine and only requires a handful of HP. You are also, in these conditions, moving a large amount of very cold ambient air around and about the engine as you move down the road.