Dr C V V Bhadram, deputy director general of IMD, Western region, said, “With the new lowest temperature, this season becomes the second coldest since 1962 when the mercury touched 7.4 degrees Celsius on January 22. We had predicted a low of 10 degrees on Tuesday but the strong northerly winds are causing a much steeper drop.”

Bhadram said the northerlies at the lower level of the atmosphere were blowing at 10 knots (19 kilometres per hour), which, according to international standards, is defined as gentle breeze. “Wednesday’s wind force was at times recorded at 15 knots,” he said, adding that 15 knots was defined as moderate breeze (28 kmph).

When wind speed mingles with the air temperature, the result is an apparent temperature (that which is felt on exposed skin) known as wind chill factor, the National Weather Service (NWS) of the United States government states.

Bhadram clarified, “These measurements taken for wind speed are strictly at the lower levels, but the impact on the atmosphere depends on the speed at different layers of atmosphere. More discomfort is experienced due to this factor.”