From uneasy to unbearable: Delhi heat at dangerous levels

NEW DELHI: It was another unbearably hot and humid day in the Capital, with Delhi’s heat index (HI) or the ‘real feel’ of temperature on Tuesday being recorded at 53 degrees as high humidity levels combined with maximum temperature of 40-44 degrees across the city worsened the sultry conditions prevailing in the Capital.

The wet-bulb temperature in Delhi also rose to 33.7 degrees, the highest so far this year, after hitting 32.11 degrees on Monday.

The heat index (HI) is a function of maximum temperature and humidity, but calculated in the shade. The wet-bulb temperature takes into account maximum temperature, humidity, wind speed, and solar radiation, and is calculated in the sun (under direct sunlight).

Wet-bulb temperatures of over 32 degrees makes it difficult for even fit and acclimatised people to work outdoors. At a wet-bulb temperature of 35 degrees, humans can no longer regulate body temperatures, leading to heatstrokes and potential collapse.

The India Meteorological Department (IMD) said moisture-laden easterly winds are keeping humidity levels in the capital as high as 45-74%, and added that relief is only expected with monsoon likely to reach Delhi on June 30 or July 1.

Safdarjung, Delhi’s base station for weather, recorded a maximum of 41.5 degrees Celsius (°C) on Tuesday — four degrees above normal for this time of the year, while Najafgarh was Delhi’s hottest location, with a high of 44.2°C.

Despite high humidity levels, rainfall generally eluded Delhi, with only isolated parts receiving a drizzle. The IMD said only the Ridge weather station recorded ‘trace’ rainfall between 8.30am and 5.30pm.

The IMD has a yellow alert in place for the Capital for Wednesday, forecasting light rainfall, accompanied by gusty winds. However, the maximum temperature is expected to be around 42 degrees and the humidity levels are also expected to remain high.

Also, there is an orange alert on Thursday, and the IMD has asked the public to be careful of a weather phenomenon — stating Delhi could see light to moderate showers with gusty winds touching 40 km/hr, which will bring down the maximum temperature to around 35 degrees. The IMD on Tuesday announced conditions were favourable for the southwest monsoon to advance into the remaining parts of Bihar, some more parts of Uttar Pradesh and some parts of Uttarakhand, Himachal Pradesh and Jammu and Kashmiri during next 24 hours. Earlier, on Monday, the monsoon had advanced into most parts of Arabian Sea and most parts of Gujarat.

“In the subsequent 48 hours, after June 29, the southwest monsoon will advance into the remaining parts of the Arabian Sea and Gujarat, some parts of Rajasthan, remaining parts Madhya Pradesh, entire Uttar Pradesh and Uttarakhand, Himachal Pradesh and Jammu and

Kashmiri, some parts of Punjab, Haryana and Chandigarh and entire Delhi,” the IMD said in a statement.

RK Jenamani, scientist at IMD, said most parts of Delhi saw particularly high temperatures — four to six degrees above normal. “This, along with humidity levels of around 50% made it another extremely uncomfortable day. During such a period, one has to limit exposure outside and ensure they keep themselves hydrated,” he said, stating while the rain on Wednesday should provide temworse porary relief, Thursday’s spell is required to bring an end to this hot and humid spell.

“We have been monitoring the progress of the monsoon and conditions have now become favourable for it to advance considerably in the next three days or so. Delhi should see the onset by June 30, or it will be declared by July 1,” Jenamani added.

The normal date of the onset of the monsoon for the capital is June 27. Last year, the monsoon arrived in the city 16 days late on July 13.

MAX TEMPERATURE

RELATIVE HUMIDITY

HEAT INDEX

WET-BULB TEMPERATURE