Parts of the national capital reeled under a cold wave on Tuesday as its minimum temperature fell below that of hill stations Dharamshala and Nainital.With a high windchill factor -- a measure of the rate of heat loss from skin that is exposed to the air -- in play, cold day conditions prevailed in some parts of the city such as Palam and Jafarpur.A cold day is when the minimum temperature is less than or equal to 10 degrees Celsius below normal and the maximum temperature is at least 4.5 degrees below normal. A severe cold day is when the maximum is 6.5 degrees or more below normal.
