NEW DELHI: India’s heatwave crisis extends beyond just soaring temperatures crossing 45°C routinely. It involves a relentless persistence of high temperatures throughout the day, and night, with no relief in sight. The situation seems to be becoming more severe, characterised by increased humidity and prolonged heatwave conditions that persist into warm nights.
According to the WHO Housing and Health Guidelines, indoor air temperatures should not consistently exceed 24°C to prevent heat-related health risks and autonomic disruption during sleep. There are many factors, however, that contribute to hot days and warm nights in the country, especially in urban centres.
Environmental causes
The ongoing weather conditions are due to the unabated flow of hot north-westerly winds coming from the desert region across Rajasthan, Punjab, Haryana till central India. These winds are expected to intensify as the country braces for a harsher summer. Moreover, a possible onset of El Nino phenomenon could disrupt monsoon rains and prolong heat stress.
Dry soils and rainfall deficit have also contributed the current heat cycle. When soil is dry, solar energy heats air more and amplify extreme heatwaves. Experts point out that the factors like heat island effects in cities are becoming a mojor factor in prolonging heat spells. Cities are increasingly functioning like heat traps, absorbing heat during the day and releasing it slowly at night, leaving millions exposed to prolonged thermal stress.
Humidity too causes heat stress. Studies show that India’s average relative humidity appears to have shifted upward in the recent half of the decade. In the 2015–2019 period, the India-wide average humidity was about 67.1%, while in the 2020–2024 period, it increased to about 71.2%.
Why UP is hot, not Rajasthan
While traditionally hotter regions, like Rajasthan, are experiencing relatively normal temperatures, lesser known cities in north and central India have become the hottest location in the country. “Generally, Rajasthan reports higher temperature,” said Mahesh Palawat, a weather expert at Skymet, “but this time southwest winds from the Arabian Sea are blowing over Gujarat and Rajasthan and keeping the temperature under check.”
On the other hand, Banda district in Uttar Pradesh has recently gained national attention as India’s hottest district, with temperatures soaring above 48°C in the past few days. Meteorologists attribute this extremely high temperature to a persistent anti-cyclone in the mid-tropospheric level, which leads to the downward movement of warmer air, exacerbated by the region’s black soil and plateau, which acts as an efficient heat absorber and releases warmth slowly at night. This means the ground fails to cool down adequately before dawn.
“Banda’s proximity to the Tropic of Cancer results in intense, direct solar radiation during summer months. Present weather conditions further amplify the soaring temperatures,” explained Atul Kumar Singh, scientist at the Weather Forecasting Centre in Uttar Pradesh.
Hot days warm nights
North-western winds from the desert region causing heatwave in north, central India
Heat island effect in cities adding to heat woes in populous urban centres
Between 2015-19 and 2020-24 periods, humidity in the country increased by over four percentage points
Banda in UP is India’s hottest district, with experts saying this extremely high temp to a persistent anti-cyclone as the ground fails to cool down before dawn
South-west winds from Arabian sea keeping Rajasthan cooler