The Western Disturbance, which was moving across Western Himalayas has been instrumental in this increase in minimums over Delhi, Haryana, Punjab and West Uttar Pradesh.
Whenever a Western Disturbance approaches the Western Himalayas, it changes the wind direction from north-westerly to south easterly leading to increase in minimums. The sky sometimes becomes partly cloudy to increase the humidity levels.
Now, the Western disturbance has already moved eastwards. Dry and icy cold winds from of Western Himalayas commence once again over Northwest and Central parts of the country. These cold winds will drop the minimum temperature Punjab, Haryana, Delhi, Rajasthan, Uttar Pradesh and Madhya Pradesh.
Delhi may witness a minimum at 7 or 8 degree in the coming days. Cold wave like conditions are possible over parts of Punjab, Haryana, Rajasthan and Madhya Pradesh.