The India Meteorological Department (IMD) has issued a yellow alert, warning of a dust storm or thunderstorm with winds gusting up to 50 kilometres per hour in the national capital on Wednesday.

There is also a possibility of very light rain in parts of the city. The maximum temperature at the Safdarjung Observatory, Delhi's base station, is likely to settle around 38 degrees Celsius.

The minimum temperature was recorded at 28.8 degrees Celsius which was four notches above normal for this time of the year.

As a result of a western disturbance affecting northwest India, a cloudy sky is predicted over the capital for the next three days.

The mercury is set to rise by four to five notches over the next six days. However, no heat wave is predicted.

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.

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.

The city's normal monthly average temperature in April is 36.30 degrees Celsius.