Mercury dips to 10c, IMD may declare a cold wave

Wind chill factor is taken into account while declaring the cold wave situation. Wind chill factor is a measure of the rate of heat loss from skin that is exposed to the air.
The wind chill effective minimum temperature (WCTn) is defined as the effective minimum temperature due to wind flow. For eg: when the minimum temperature is 15 degree Celcius and the wind speed is 10 mph, WCTn will be 10.5 degree celsius.
Departure of WCTn from normal minimum temperature is from –5° C to –6° C where normal minimum temperature above 10 degree Celsius and from –4 degree Celsius to –5 degree Celsius elsewhere, Cold Wave is declared.
For declaring cold wave WCTn only is used and when it is below 10 degree Celsius only, cold wave is considered (this criteria does not hold for coastal stations).
Cold wave is declared when WCTn is below 0 degree celsius irrespective of the normal minimum temperature for those stations.
Indian Meteorological Department (IMD) declares a cold wave in India.

Since the minimum temperatures touched 10 degree celsius in Delhi and NCR region, the IMD was about to declare that the region was under the cold wave.

Today Current Affairs Upsc Exam Syllabus & Previous Yearpaper.