Introduction
Northwest India experienced an early onset of cold conditions this October, accompanied by reduced wind speeds and worsening air quality. Meteorological data and forecasts suggest an increasing probability of La Niña conditions, raising expectations of colder winters, especially across the Indo-Gangetic plains. However, recent studies indicate that the connection between La Niña and India’s winter temperatures is more complex than previously thought.
La Niña represents the cooler phase of the El Niño–Southern Oscillation (ENSO) cycle, occurring in the central and eastern Pacific Ocean. During this phase, trade winds strengthen and push warm surface waters westward toward Asia, leading to cooler-than-normal sea surface temperatures in the eastern Pacific. This often results in enhanced rainfall over Indonesia, Australia, and the Indian subcontinent.
La Niña events typically occur every 2–7 years and may last for about 9–12 months. Its opposite phase, El Niño, warms the Pacific waters, often causing drought-like conditions in India, whereas La Niña tends to strengthen the Indian monsoon and may influence winter patterns.
During La Niña years, cold air masses from Siberia and Central Asia may extend southward, bringing colder air into northern India. Western disturbances—storm systems originating from the Mediterranean—interact with these cold air masses, triggering snowfall in the Himalayas and sharp temperature drops across the northern plains. The north–south trough in the jet stream often deepens, altering rainfall and temperature distribution.
However, the degree of cooling depends on several factors, including:
• The strength and duration of the La Niña event.
• Interaction with the Indian Ocean Dipole (IOD).
• Local geographical conditions, particularly the Himalayas and the Indo-Gangetic plains.
Delhi’s October 2020 was the coldest since 1962, with a minimum temperature of 17.2°C, partially attributed to La Niña. Similarly, cold winters were recorded in 2007, 2010, 2011, and 2012—all La Niña years. Yet, recent winters between 2020 and 2024, despite La Niña conditions, have shown above-normal temperatures, indicating that La Niña does not always lead to harsher winters.
According to India Meteorological Department (IMD) data:
• The mean temperature anomaly for Jan–Feb 2024 was +0.37°C.
• For 2023, it was +0.83°C.
• Even in 2022—a La Niña year—the anomaly was nearly normal, suggesting a weaker correlation between La Niña and cold winters in recent years.
Scientists attribute these inconsistencies to multiple global and regional factors:
• Global warming has raised baseline temperatures, offsetting La Niña’s cooling influence.
• Prolonged La Niña phases (2020–2024) have failed to reproduce historic patterns due to changes in the jet stream and polar vortex behavior.
• India’s topography, particularly the Himalayas, restricts cold air intrusions from the north.
As Dr. D.P. Sreejith from the IMD explains, “recently, there has been no direct connection between harsher winters and La Niña,” emphasizing that regional climatic dynamics now play a larger role than global oscillations.
• Agriculture: Early frost can damage crops such as potatoes, mustard, and pulses in northern India.
• Air Quality: Cold, stagnant air worsens pollution in major cities like Delhi and Lucknow.
• Energy Demand: Extended cold spells increase electricity and fuel consumption.
• Tourism: Heavy snowfall boosts tourism in Himachal Pradesh, Uttarakhand, and Jammu & Kashmir.
1. Does La Niña always bring cold weather to India?
Not necessarily. While La Niña can coincide with cooler winters, recent patterns show warmer-than-average conditions, especially during extended La Niña phases.
2. Why was Delhi’s 2020 winter exceptionally cold?
The strong La Niña phase, combined with frequent western disturbances, led to repeated cold waves during the 2020 winter season.
3. Which regions of India are most affected?
Northwestern India and the Himalayan belt experience the strongest La Niña impacts, while southern India generally feels marginal effects.
4. How do global agencies track La Niña?
Institutions such as the NOAA (U.S.) and WMO (World Meteorological Organization) monitor Pacific sea surface temperatures and issue forecasts using ENSO models.
5. Can La Niña influence both the monsoon and winter?
Yes. La Niña can strengthen the southwest monsoon and occasionally bring colder winters, though outcomes depend on timing and interaction with other climatic systems.
La Niña, the cooler phase of the ENSO cycle, develops when Pacific waters cool abnormally, altering global wind and rainfall patterns. Traditionally, it has been linked to stronger monsoons and colder Indian winters. However, recent years show warmer winters despite La Niña, due to shifting jet streams, Himalayan barriers, and rising global temperatures. Scientists now emphasize regional climatic influences as more decisive than global oscillations in determining India’s winter severity.
Updated on October 28, 2025.
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