Delhi witnessed the first severe heat wave of the year today with the maximum temperature at Safdarjung Observatory, considered the official marker for the city, rising to 43 degrees Celsius, the highest this year so far.
A severe heat wave was witnessed in Lodhi Road, Ridge and Pusa areas, where the mercury soared to 42.6 degrees Celsius, 43.4 degrees Celsius and 44.3 degrees Celsius, respectively, seven notches above the average temperature.
Najafgarh (44.4 degrees Celsius), Pitampura (44.3 degrees Celsius) and Mungeshpur (44.3 degrees Celsius) also reeled under a severe heat wave.
For the plains, a "heat wave" is declared when the maximum temperature is more than 40 degrees Celsius, and at least 4.5 notches above normal.
A "severe" heat wave is declared if departure from normal temperature is more than 6.5 degrees Celsius, according to the India Meteorological Department (IMD).
"Usually, the capital witnesses heat waves till June 20. The increase in the maximum temperature this time can be attributed to the delay in the arrival of the monsoon," Kuldeep Srivastava, the head of the IMD's regional forecasting centre, said.
There has been no rainfall in the last three days and warm westerly winds are blowing across a major part of northwest India, which has not been covered by the monsoon yet, he said.
A heat wave is predicted in the capital on Wednesday, too.
According to the IMD, the southwest monsoon has reached Barmer in west Rajasthan, one of its last outposts, two weeks before its normal schedule but is yet to arrive in the north Indian plains including Delhi.
The northern limit of southwest monsoon (NLM) continues to pass through Barmer, Bhilwara, Dholpur, Aligarh, Meerut, Ambala and Amritsar, it said.
After arriving two days late in Kerala, the monsoon had raced across the country, covering eastern, central and adjoining northwest India seven to 10 days earlier than normal.
The meteorological office had earlier predicted that the wind system may reach Delhi by June 15, which would have been 12 days early. However, westerly winds have been blocking its advance into Delhi, parts of Uttar Pradesh, Rajasthan, Punjab and Haryana.
Normally, monsoon reaches Delhi by June 27 and covers the entire country by July 8. Last year, the wind system had reached Delhi on June 25 and covered the entire country by June 29.
However, this year, the wait for Delhi, Haryana, parts of west Uttar Pradesh, Punjab and west Rajasthan has been overdue even as the mercury and humidity have continued to soar, the IMD said, adding immediate relief was unlikely.
"Prevailing meteorological conditions, large scale atmospheric features and the forecast wind pattern by dynamical models suggest that no favourable conditions are likely to develop for further advance of southwest monsoon into remaining parts of Rajasthan, west Uttar Pradesh, Haryana, Chandigarh and Delhi and Punjab during the next six to seven days," the IMD said.