Delhi Heat Wave: Weather Officer warned of heat wave at isolated places in Delhi.
The ongoing heat wave spell tightened its grip on parts of Delhi on Sunday, with the mercury breaching the 45-degree Celsius mark in six localities.
At the Safdarjung Observatory, the city's base station, the maximum temperature settled at 44.2 degrees Celsius as against 43.9 degrees Celsius on Saturday and 42.9 degrees Celsius on Friday.
The mercury jumped to 47.3 degrees, seven notches above normal, at Mungeshpur, making it the hottest place in the capital.
Sports Complex, Pitampura, Najafgarh, Jafarpur and Ridge recorded a high of 46.6 degrees Celsius, 46.2 degrees Celsius, 46.3 degrees Celsius, 45.1 degrees Celsius and 45.7 degrees Celsius respectively.
The Met office has issued a "yellow" alert, warning of heat wave conditions at isolated places in Delhi on Monday.
The India Meteorological Department (IMD) uses four colour codes for weather warnings -- "green" (no action needed), "yellow" (watch and stay updated), "orange" (be prepared) and "red" (take action).
Mahesh Palawat, vice-president (climate change and meteorology), Skymet Weather, said Delhi, Haryana, Punjab, north Rajasthan and west Uttar Pradesh may see pre-monsoon activity on and off from June 10. The maximum temperature in the capital may drop to 40-41 degrees Celsius by Saturday.
"The monsoon will cover eastern India by June 15, which will intensify pre-monsoon activity in northwest India," he said.
A heat wave is declared when the maximum temperature is over 40 degrees Celsius and at least 4.5 notches above normal. A severe heat wave is declared if the departure from normal temperature is by more than 6.4 notches, according to the IMD.
Based on the absolute recorded temperatures, a heat wave is declared when an area logs a maximum temperature of 45 degrees Celsius.
A severe heat wave is declared if the maximum temperature crosses the 47-degree Celsius mark.