Just as large parts of northern India were beginning to breathe easier after a brief respite from scorching temperatures, the region is staring at another intense heat spell. From Punjab and Haryana to Delhi, Rajasthan and Uttar Pradesh, temperatures are expected to surge sharply over the coming days, with forecasts indicating daytime highs between 42°C and 46°C. The episode serves as a reminder that despite the southwest monsoon's arrival over Kerala, vast stretches of the country remain trapped in the transitional period between summer and monsoon—a phase increasingly characterised by extreme and recurrent heat events.
Meteorologically, the impending heatwave is not unusual. The northwestern plains of India are highly vulnerable to the arrival of hot, dry winds originating from the Thar Desert and adjoining regions of Pakistan. These winds, popularly known as the "loo", act as a conveyor belt of heat. As they sweep across arid landscapes, they accumulate thermal energy and transport it eastward, preventing localised cooling and rapidly raising surface temperatures. The effect becomes particularly severe when accompanied by a high-pressure ridge in the upper atmosphere. Such systems force air to descend, compress and warm further, creating what climatologists often describe as a "heat dome". The result is clear skies, relentless solar radiation and prolonged periods of oppressive heat.
What makes the situation more concerning is the role of land conditions. Across much of north and central India, soil moisture levels have been depleted after months of dry weather. Moist soil naturally cools the environment through evaporation, but parched ground loses this ability. Consequently, nearly all incoming solar energy is converted into sensible heat, causing temperatures near the surface to climb even faster. This feedback loop has become increasingly evident in recent years as prolonged dry spells and erratic rainfall patterns leave landscapes more vulnerable to extreme heating.
The India Meteorological Department's criteria for declaring a heatwave illustrate the seriousness of the forecast. In the plains, a heatwave is declared when temperatures exceed 40°C and remain at least 4.5°C above normal, or when the mercury touches 45°C irrespective of the departure from normal. Forecast temperatures of 42°C to 46°C across several districts therefore comfortably meet the threshold. Regions such as western Rajasthan, southern Haryana, Delhi-NCR and parts of Uttar Pradesh's Bundelkhand belt are particularly susceptible, not only because of geography but also because of rapid urbanisation, shrinking green cover and the urban heat island effect that traps heat in densely built environments.
The broader context is impossible to ignore. India experienced one of its hottest years on record in 2024, while scientific studies continue to show that climate change is making heatwaves more frequent, longer-lasting and more intense. The number of heatwave days has increased across several parts of the country over the past decade. What was once considered an occasional weather event is increasingly becoming a recurring seasonal hazard with significant economic and public health implications. Outdoor workers, farmers, construction labourers, street vendors and vulnerable populations bear the brunt of these conditions. Heat stress reduces labour productivity, strains electricity networks through surging cooling demand and places enormous pressure on public health systems.
There is, however, some relief on the horizon. Meteorologists expect a western disturbance around June 13, which could bring cloud cover, isolated rainfall and a shift in wind patterns. Such systems often provide temporary respite by disrupting the flow of hot desert winds and introducing cooler air. Yet the relief is likely to be short-lived. Until the southwest monsoon advances significantly into northern India, episodes of extreme heat are likely to recur. The challenge for policymakers is therefore no longer merely forecasting heatwaves but adapting to a future in which they become a regular feature of the Indian summer. Early warning systems, heat action plans, improved urban design, better water management and protection for outdoor workers must become central elements of climate resilience. The approaching heat spell is not just another weather event—it is a glimpse of the new normal that India must prepare for.