India Meteorological Department (IMD) has issued an 'orange' alert, warning that the mercury may soar to 46-47 degrees Celsius in parts of the city today.

The national capital has been reeling from a scorching heatwave for the last two days and weather will be worse today.

The maximum temperature at the Safdarjung Observatory, Delhi's base station, is predicted to settle at 44 degrees Celsius as against 42.5 degrees Celsius on Friday.

Delhi on Friday saw the mercury rise to 46.1 degrees Celsius at Najafgarh. The weather stations at Jafarpur and Mungeshpur had recorded maximum temperatures of 45.6 degrees Celsius and 45.4 degrees Celsius, respectively, six notches above normal for this time of the year.

A 'yellow' alert has been issued to caution people about a heatwave on Sunday.

IMD uses four colour codes for weather warnings – green (no action needed), yellow (watch and stay updated), orange (be prepared) and red (take action).

However, the weather is expected to improve next week as cloudy skies and thunder may provide some relief from the intense heat.

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 month-end had sent the mercury soaring to 46 and 47 degrees Celsius in several parts of the city.

IMD had also predicted above normal temperatures for May.

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.