Hey Stabo, it is posible that your thermostat is a bit sticky in the open state, this will cause the temp to drop as you cruise, your temp should be stable and not fluctuate in this weather. its normal for you car to be underpowered if the engine is to cold as Vtec will not kick in as some one mentioned above. I recommend a genuine thermostat and replace the oring, use genuine coolant as well. if you are going to do it your self, you must crack open the cooling system bleed nipple when filling it up with coolant as you dont want any air pockets in you engine.