All the weather stations in the capital recorded a heatwave day.
A tormenting heatwave turned Delhi into a hot cauldron on Saturday, pushing the mercury to an unbearable high of 47.2 degrees Celsius at Mungeshpur and 47 degrees Celsius at Najafgarh, both at least seven notches above the normal.
The Safdarjung Observatory, Delhi's base station, recorded a maximum temperature of 44.2 degrees Celsius, which was five notches above the normal and the highest this season so far. It was 42.5 degrees Celsius on Friday.
Delhi saw the mercury rise to 46.9 degrees Celsius at Sports Complex, 46.4 degrees Celsius at Pitampura, 45.8 degrees Celsius at Jafarpur and 45.4 degrees Celsius at Ridge and Ayanagar.
All the weather stations in the capital recorded a heatwave day, the India Meteorological Department (IMD) said.
Weather forecasters predicted the heatwave spell to worsen on Sunday. An 'orange' alert has been issued for Sunday to caution people about a severe heatwave.
The IMD uses four colour codes for weather warnings -- green (no action needed), yellow (watch and stay updated), orange (be prepared) and red (take action).
This is the fifth heatwave in the capital this summer.
With scanty rains owing to feeble western disturbances, Delhi had recorded its second hottest April this year since 1951 with a monthly average maximum temperature of 40.2 degrees Celsius.
A heatwave at the end of that month had sent the mercury soaring to 46 and 47 degrees Celsius in several parts of the city.
"Hot and dry westerly winds sweeping the Delhi-NCR region will push the mercury further up. It is likely to hit the 45-degree mark at Safdarjung on Sunday," said Mahesh Palawat, Vice President (Meteorology and Climate Change), Skymet, a private weather forecasting agency.
"A cyclonic circulation over Punjab and Haryana will induce pre-monsoon activity which will provide some relief from the intense heat on Monday and Tuesday," he said.
The IMD said a thunderstorm or a dust storm is likely in the national capital on Monday.
Delhi received a minuscule 0.3 mm of rainfall in April against a monthly average of 12.2 mm. March saw no rainfall against a normal of 15.9 mm. The IMD had predicted above-normal temperatures in May.
A heatwave is declared when the maximum temperature is over 40 degrees Celsius and at least 4.5 notches above the normal. A severe heatwave is declared if the departure from normal temperature is more than 6.4 notches, according to the IMD.
Based on absolute recorded temperatures, a heatwave is declared when an area logs a maximum temperature of 45 degrees Celsius.
A severe heatwave is declared if the maximum temperature crosses the 47-degree Celsiu
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