India is witnessing an intense summer marked by heatwaves, unseasonal rainfall, rising humidity, and concerns regarding the possible return of El Niño conditions. These climatic events are influencing rainfall patterns, agricultural productivity, water availability, and public health across the country.
The India Meteorological Department (IMD) has forecast fresh Western Disturbances over North India between May 11 and May 13, 2026, while global agencies have warned of a possible El Niño year ahead. Along with increasing heat stress and rising “feels like” temperatures, these climate phenomena are becoming increasingly relevant for governance, disaster management, and climate adaptation.
Western Disturbance
A Western Disturbance is an eastward-moving rain-bearing weather system originating over the Mediterranean region, Iran, and Afghanistan. These systems gather moisture from the Mediterranean Sea, Black Sea, Caspian Sea, and Arabian Sea before reaching the Indian subcontinent.
Western Disturbances are extra-tropical cyclones formed due to interactions between cold polar air masses and warm tropical air masses. They travel through the subtropical westerly jet stream, a high-altitude fast-moving air current flowing west to east over the Himalayan region.
They mainly affect:
- Northwestern India
- Pakistan
- Afghanistan
- Himalayan regions
Western Disturbances are most common during winter (December–March) and are important for:
- Winter rainfall in North India
- Snowfall in the Himalayas
- Rabi crop productivity
However, during summer, they can cause:
- Unseasonal rainfall
- Thunderstorms
- Hailstorms
- Sudden temperature fluctuations
Such weather events can damage crops, disrupt transport, and increase humidity levels.
El Niño and ENSO
The El Niño Southern Oscillation (ENSO) is a global climate phenomenon involving changes in Pacific Ocean temperatures and atmospheric circulation.
ENSO has three phases:
- El Niño – Warm phase
- La Niña – Cool phase
- Neutral phase
These cycles usually occur every 2–7 years.
Under normal conditions, trade winds push warm ocean water towards Indonesia, keeping the eastern Pacific near South America cooler. During El Niño, these trade winds weaken, causing unusually warm waters in the eastern Pacific Ocean.
Impact of El Niño on India
El Niño generally weakens India’s southwest monsoon and can lead to:
- Delayed monsoon onset
- Below-normal rainfall
- Drought-like conditions
- Reduced agricultural output
- Frequent and severe heatwaves
The U.S. Climate Prediction Center has projected a 61% probability of El Niño developing between May and July 2026.
La Niña and Monsoon
La Niña is the opposite phase of ENSO, characterised by cooler-than-normal eastern Pacific waters.
It generally strengthens the Indian monsoon by enhancing moisture-bearing winds over the Indian Ocean.
Effects of La Niña include:
- Above-normal monsoon rainfall
- Better agricultural conditions
- Increased risk of floods and landslides during extreme rainfall events
Thus, both El Niño and La Niña significantly influence India’s economy, agriculture, and water security.
Heat Waves in India
A heat wave is a prolonged period of unusually high temperatures significantly above the normal average of a region.
According to the IMD:
- Heat wave conditions in plains occur at 40°C or above
- In hilly areas, the threshold is 30°C
- Severe heat waves occur when temperatures exceed normal levels by more than 6.4°C
Irrespective of normal temperatures:
- Heat wave: 45°C or above
- Severe heat wave: 47°C or above
Heatwaves become more dangerous due to:
- High humidity
- Strong dry winds
- Longer duration of exposure
India has witnessed increasing frequency and intensity of heatwaves due to climate change and urban heat island effects.
Wet Bulb Temperature and Heat Stress
The normal temperature measured by a thermometer is called Dry Bulb Temperature. However, it does not account for humidity.
Wet Bulb Temperature measures the lowest temperature achievable through evaporation and reflects the body’s ability to cool itself through sweating.
High humidity reduces sweat evaporation, making extreme heat feel more dangerous.
According to the Intergovernmental Panel on Climate Change (IPCC):
- Sustained exposure above 35°C wet bulb temperature can be fatal
- Above 31°C, heavy physical activity becomes dangerous
Outdoor workers, elderly people, and individuals with heart disease or diabetes are particularly vulnerable.
“Feels Like” Temperature and Heat Index
The “Feels Like” temperature, also called apparent temperature, represents how hot or cold weather actually feels to the human body.
It combines:
- Actual air temperature
- Humidity
- Wind conditions
Heat Index
The Heat Index combines temperature and humidity to estimate heat stress on the body.
Wind Chill Index
The Wind Chill Index combines temperature and wind speed to estimate how cold weather feels.
These indicators are important for issuing public health advisories during extreme weather events.
Conclusion
India’s summer of 2026 highlights the growing impact of climate variability and extreme weather events. Western Disturbances, El Niño conditions, heatwaves, rising humidity, and increasing “feels like” temperatures are affecting agriculture, health, water security, and the economy.
With climate change intensifying weather extremes, strengthening forecasting systems, heat action plans, climate-resilient agriculture, and public awareness will be essential for reducing vulnerability and improving climate adaptation in India.