I think this is normal behaviour. Accurate temperature is displayed when the car travels at a high speed constantly. Stationary temperatures are not very accurate.
In addition to that, Rawalpindi does not have 0 C nowadays. Thr minimum drops to 5 C or 6 C. I think you're good to go but if you still want to clean it, it's behind the bumper in front of the battery, below the headlight.
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