What Happened
- The India Meteorological Department (IMD) has forecast above-normal maximum temperatures and more-than-usual heatwave days across most of India during March–May 2026.
- IMD Director-General Mrutyunjay Mohapatra stated that minimum night temperatures are likely to remain above average across most of India starting March itself.
- States expected to face above-normal heatwave days include west Rajasthan, Gujarat, Haryana, Punjab, southern and eastern Maharashtra, eastern UP, Bihar, Jharkhand, Gangetic West Bengal, Odisha, Chhattisgarh, Telangana, and Andhra Pradesh.
- The early heat signal poses risks for public health, water resources, power demand, and agriculture — especially for vulnerable groups such as the elderly, children, and outdoor workers.
- The forecast is based on sea surface temperature patterns and circulation anomalies linked to warming ocean conditions.
Static Topic Bridges
IMD's Definition and Classification of Heatwaves
A heatwave, as defined by IMD, is a condition of abnormally high temperatures relative to the expected maximum temperature of a region. The declaration is based on two criteria: an absolute temperature threshold and a departure from normal.
- Plains: Heatwave declared when maximum temperature reaches 40°C or above AND departs from normal by 4-6°C; severe heatwave when departure ≥ 6°C (or ≥ 7°C if normal max ≤ 40°C)
- Hill regions: Maximum temperature of 30°C or above required to declare a heatwave
- Absolute criterion: If actual maximum temperature reaches 45°C or above (irrespective of normal), heatwave is declared
- IMD issues heatwave warnings as part of its Color-Coded Alert system: Yellow (Watch), Orange (Alert), Red (Warning)
- Heatwave conditions typically prevail from March to June in India; most intense in April-May
Connection to this news: The IMD's 2026 summer forecast warns of above-normal heatwave days across these IMD-defined thresholds, triggering pre-emptive government and public health advisories.
National Action Plan on Climate Change (NAPCC) and Heat Action Plans
India's response to climate change is anchored by the NAPCC, launched in 2008, which includes eight national missions. The National Mission for Strategic Knowledge for Climate Change (NMSKCC) and the National Mission for Enhanced Energy Efficiency (NMEEE) are most directly relevant to heat stress. At the operational level, state and city governments prepare Heat Action Plans (HAPs) — pre-planned responses that include early warning systems, public awareness, cooling centres, and hospital preparedness protocols.
- NAPCC (2008): 8 missions including National Solar Mission, National Water Mission, Green India Mission, Sustainable Habitat Mission, etc.
- Heat Action Plans: First introduced in Ahmedabad in 2013 after the 2010 heatwave killed hundreds; now adopted by over 130 cities/states
- Ahmedabad's HAP is internationally recognised as a model for reducing heat mortality
- Key HAP elements: Colour-coded alerts linked to IMD forecasts, inter-departmental coordination, night shelter and cooling centre activation, Jal Mitra (water distribution) programmes
- India's heatwaves are being exacerbated by the urban heat island effect in large cities
Connection to this news: The 2026 IMD forecast directly triggers Heat Action Plan activation across vulnerable states; the forecast underscores why scaling HAPs is essential.
Wet-Bulb Temperature and Human Survivability
Beyond simple air temperature, the wet-bulb temperature (WBT) — which accounts for both heat and humidity — is a more accurate measure of heat stress on the human body. A WBT of 35°C is considered the theoretical upper limit of human survival even for fit individuals at rest in the shade. Research suggests parts of India are already approaching dangerous WBT thresholds, particularly in humid coastal and Gangetic plain regions.
- Wet-bulb temperature: Measures temperature a thermometer would read if its bulb were covered by a wet cloth (accounts for evaporative cooling)
- WBT 35°C = absolute physiological limit; core body temperature cannot be maintained
- India risk zones: Bihar, Jharkhand, Odisha, parts of Gangetic plains show elevated WBT during summer
- Humans typically experience dangerous conditions at WBT above 30°C even with limited physical activity
- Climate models project India could see WBT 35°C events annually by 2100 under high-emission scenarios
Connection to this news: The above-normal temperature forecast for 2026, especially in humid states like Odisha and Jharkhand, pushes these regions closer to dangerous wet-bulb thresholds for outdoor workers and the elderly.
Key Facts & Data
- IMD's summer forecast: Above-normal maximum temperatures March–May 2026, more heatwave days than average
- States at highest risk: West Rajasthan, Gujarat, Haryana, Punjab, southern Maharashtra, Odisha, Chhattisgarh, Telangana, AP, Gangetic WB
- IMD heatwave threshold (plains): Max temperature ≥ 40°C + departure from normal ≥ 4-6°C
- IMD DG: Mrutyunjay Mohapatra
- NAPCC launched: 2008, includes 8 national climate missions
- First Heat Action Plan in India: Ahmedabad, 2013
- Wet-bulb temperature survivability limit: 35°C (theoretical upper bound for humans)
- India's climate commitment: Net zero by 2070 (declared at COP26, Glasgow, 2021)
- SDG 13: Climate Action — calls for urgent measures to combat climate change and its impacts