40.9°C in national capital but humidity takes ‘real feel’ up to 45°C

Experts attributed the increased humidity to moist winds from the east, and said similar conditions are likely to prevail.

Warm and sultry conditions capped the weekend for the Capital, with Delhi recording a high of 40.9°C, a number not unusual when seen in isolation, but made worse with significant humidity in the air that made it feel hotter than recent days.

With a relative humidity varying between 54% in the morning to about 30% in the evening, according to India Meteorological Department data.

With a relative humidity varying between 54% in the morning to about 30% in the evening, according to India Meteorological Department data, the heat felt more like a 45°C day – a calculation known as the heat index or, more colloquially, “real feel”.

The heat index is a calculation that represents conditions in the shade and prolonged exposure to a heat index of 26°–32°C will likely cause fatigue in many people, while 32°–40°C is widely associated with sunstroke, and 40°–54°C with heatstroke.

Experts attributed the increased humidity to moist winds from the east, and said similar conditions are likely to prevail. “Easterly, moist winds are blowing over the northwestern region for past 2 days. There is a cyclonic circulation over central Pakistan, its trough is extending up to Delhi, “said Mahesh Palawat, vice president, climate and meteorology at Skymet Weather.

There were dust storms and lights rain in some parts of Rajasthan and some of this can be expected in the Capital during the next couple of days, he added.

A second official too said humidity was higher than usual, but the weather did not breach the heatwave threshold. “We are not expecting any major heatwave conditions over northwest India for next 5-6 days. Today humidity is slightly high. A feeble western disturbance is approaching, due to these there may be very light thunderstorm, rain in some parts so we are not expecting maximum temperatures to spike too much,” said Naresh Kumar, scientist at IMD.

Sunday’s maximum of 40.9°C, to be sure, was degree above what is normal for this time of the year.

The IMD said the maximum temperature is likely to remain at similar levels, perhaps even rising slightly to 42°C on Monday, which means the threat remains of weather that may not be numerically intense, but could still pose a threat to human health.

A second measure to put the heat into perspective is through wet bulb temperature, which is relevant for exposure in the sun. Sunday’s wet bulb temperature in Delhi, taking into account Safdarjung station’s readings, was around 28°C during the day, not far from the 30°C beyond which exposure can be life threatening.

According to IMD’s weekly forecast, the maximum temperature is expected to hover around 42°C on Monday while the minimum may touch 24°C. A partly clear sky along with strong surface winds with a speed between 30-40KMPH are expected on Monday.

IMD’s seven-day forecast pegged the day temperature to hover in the 41-42 °C range with light rain or drizzle on Tuesday.

On Saturday, the maximum temperatures were in the range of 44-46°C over many parts of West Rajasthan, some parts of Madhya Pradesh and Vidarbha; in the range of 41-44°C over rest of northwest and central India and some parts of north Peninsular India.

With scientists warning 2023 will likely be another year marked by dangerously high temperatures, signs of strain are emerging across Asia as the heat wave that started in April continues to blast through the region, following a pattern of increasing extreme weather caused by the accumulation of greenhouse gases in the atmosphere.

In India, however, it played out differently this year with an unusually cool second-half of April, when multiple spells of rain hit the northwest.

Nonetheless, the pattern has left concern among experts, who say the threat of El Nino conditions expected in the next few months, coupled with the lower than usual warming of north and northwest India, could affect monsoon rains.