The Safdarjung Observatory, Delhi’s base station, recorded a maximum temperature of 44.2 degrees Celsius, which was five notches above 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.
Weather forecasters said the heatwave spell is set to worsen on Sunday.
An ‘orange’ alert has been issued to caution people about a severe heatwave on Sunday.
The IMD uses four color codes for weather warnings – green (no action needed), yellow (watch and stay updated), orange (be prepared) and red (take action).
However, cloudy skies and thunder may provide some relief from the intense heat next week.
This is the fifth heatwave – one in March and three in April – in the capital this summer season.
With scanty rainfall 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 the month had sent the mercury soaring to 46 and 47 degrees Celsius in several parts of the city.
The capital got a miniscule 0.3 mm of rainfall in April against a monthly average of 12.2 mm. March saw nil 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 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 Celsius mark.