Max increases in Delhi but no heatwave for second day

Mercury rises in Delhi with no heatwave conditions for second day, max temp at 43°C. Chance of dust storm, scattered rain over the weekend.

The mercury rose marginally across the city on Friday, but no heatwave conditions were recorded in the region for a second consecutive day, the India Meteorological Department (IMD) said.

Safdarjung, representative of Delhi’s weather, recorded a maximum of 43 degrees Celsius (°C), which was three degrees above normal. (Raj K Raj/HT Photo)

Safdarjung, representative of Delhi’s weather, recorded a maximum of 43 degrees Celsius (°C), which was three degrees above normal. It was 41.2°C a day earlier. Forecasts suggested that the Capital’s maximum would hover between 42°C and 43°C over the weekend too, with chances of a dust storm and scattered rain likely in Delhi and National Capital Region (NCR).

The Capital was hit by a dust storm late on Thursday night, with wind speed touching a maximum of 74 km/hour at Safdarjung at around 11.30pm, IMD said. Wind gusting at a speed of 30-40km/hour was also recorded in the early hours of Friday, with IMD forecasting similar weather to continue over the weekend.

“Days should continue to remain warm, with late evening and night-time recording gusty winds. There are also chances of isolated parts of Delhi recording a drizzle late on Saturday,” said an IMD official.

Heatwave conditions abated in Delhi on Thursday after 12 consecutive days, after the Capital saw light rain and gusty winds late on Wednesday, providing a temporary cooling effect.

IMD classifies it as a “heatwave” when the maximum temperature is over 40°C, while also being 4.5 degrees or more above normal. No weather station met this criteria on Friday.

The city saw northeasterly winds on Thursday, with the wind direction changing to southwesterly in the first half of Friday and to westerly in the second half. While easterly winds tend to bring moisture, westerly winds are drier and come from Rajasthan. Southwesterly winds can also add some moisture from the Arabian Sea.

IMD has predicted the wind direction to predominantly remain westerly to northwesterly on Saturday, making for a dry and hot day. “Only towards late evening and night we may see some dust storm activity, with some light rain possible too,” the official added.

Meanwhile, Delhi’s minimum temperature was 28°C, which was around normal for this time of the season. It was 24.6°C a day earlier. The minimum is forecast to be around 29°C over the weekend.

IMD said Delhi’s relative humidity was between 25% and 57% on Friday. This gave Delhi a heat index (HI) or “real feel” of 46.5°C. The HI was 41.9°C on Thursday.

Delhi’s wet-bulb temperature, another indicator of comfort level outside, was between 25.1°C and 25.5°C on Friday. The highest wet-bulb a day recorded earlier was 27°C. A wet-bulb temperature of 32°C or higher makes it difficult for even fit and acclimatised people to work outdoors for long and at a wet-bulb temperature of 35°C — the maximum threshold — humans can no longer regulate body temperatures, leading to heatstrokes and potential collapse. In Delhi, this tends to be over 30°C, usually in July and early August, when there is moisture intrusion, due to the monsoon.