New Delhi: Residents of central, northwestern, and northeastern India are likely to experience a harsher winter than usual this season, according to the India Meteorological Department (IMD). Officials have projected higher than normal cold wave days over several regions, warning that the polar vortex and ongoing La Niña conditions could drive temperatures significantly below the seasonal average in key parts of the country.

Regions Likely to Experience Cold Wave

Spatial temperature maps released by the IMD indicate that states such as Haryana, Rajasthan, Delhi, and Gujarat are expected to record below-normal minimum temperatures during the winter months. Across these regions, the number of cold wave days—days when minimum temperatures drop below 15°C and fall below roughly 90% of daily historical averages—is expected to be higher than usual. Normally, northwest India experiences five to six cold wave days between December and February. This winter, forecasts suggest one to four or more additional cold wave days may occur in several areas, heightening discomfort and potentially affecting agriculture, transport, and public health.

The IMD also projects that most parts of central India, as well as adjoining peninsular and northwest regions, will experience normal to below-normal minimum temperatures. In contrast, other areas of the country may see slightly above-normal minimum temperatures. This uneven pattern indicates that while some regions will grapple with unusually cold nights, others could experience milder conditions.

Maximum Temperatures and Regional Variations

While minimum temperatures are expected to be below normal in the affected regions, daytime or maximum temperatures are predicted to follow a slightly different pattern. Most parts of India could see above-normal day temperatures during December. However, parts of central India, along with adjoining northwest and peninsular regions, are likely to record normal to below-normal maximum temperatures, suggesting a marked diurnal range that could exacerbate the sensation of cold during mornings and nights.

Rainfall Outlook for December

The IMD has also provided a preliminary outlook on rainfall for December. Overall, monthly precipitation across the country is expected to remain within the normal range—79 to 121% of the long-period average (LPA). Certain areas in peninsular and west-central India, as well as parts of east-central and northeast India, may receive above-normal rainfall. Conversely, the rest of the country is projected to experience below-normal rainfall. These rainfall patterns, coupled with cold wave conditions, could have implications for agriculture and water resource management, particularly in regions already facing moisture deficits.

Role of the Polar Vortex

The forecasted cold conditions are largely influenced by the polar vortex, a large-scale area of low pressure and extremely cold air that surrounds the Earth’s poles. While the polar vortex exists year-round, it strengthens in winter, often sending frigid air masses southward into mid-latitudes, including India. According to OP Sreejith, scientist and head of the Climate Monitoring and Prediction Group at the IMD, “Below normal temperatures and cold wave conditions over Madhya Pradesh in November were influenced by the polar vortex and La Niña conditions. Now again, the polar vortex is impacting temperatures over northwest and central India.”

The interaction between the polar vortex and local atmospheric conditions is expected to maintain below-normal temperatures for several weeks, particularly in northern and central parts of the country.

Impact of La Niña on Winter Conditions

La Niña, the periodic large-scale cooling of ocean surface temperatures in the central and eastern equatorial Pacific Ocean, is another major factor influencing this winter’s climate. La Niña events typically affect tropical atmospheric circulation, altering wind patterns, pressure systems, and rainfall distributions. For India, La Niña is associated with harsher winters, especially in northern and central regions.

IMD officials indicate that La Niña is expected to continue through the Northern Hemisphere winter, with a likely transition to ENSO-neutral conditions in January-March 2026, with a 61% probability. This prolonged La Niña influence, in combination with the polar vortex, is expected to result in sustained cold wave conditions in several regions and below-normal temperatures across large swathes of northwest and central India.

Recent Temperature and Rainfall Trends

Data from November highlights the early signs of the winter pattern. Minimum temperatures were normal to below normal over most parts of the country, except in many areas of northeast India and Peninsular India. Rainfall, however, showed a significant spatial disparity. The country experienced a 42.8% deficiency overall, with northwest India recording a 78.1% shortfall, central India facing a 51.3% deficit, and South Peninsula observing a 43.6% deficiency. In contrast, east and northeast India had 8.9% excess rainfall. This uneven precipitation pattern combined with lower temperatures suggests that the cold wave may impact regions already stressed by moisture deficits.

Understanding Cold Waves

A cold wave is declared when the minimum temperature in a region is significantly below the normal threshold—roughly 90% of historical daily averages—and falls below 15°C for at least three consecutive days. These events are closely monitored by the IMD due to their impact on human health, agriculture, energy demand, and daily life. Higher-than-normal cold wave days can increase the risk of frost, adversely affect winter crops, strain power supply due to increased heating needs, and lead to health issues such as hypothermia and respiratory illnesses.

Implications for Citizens and Authorities

The IMD’s winter forecast is particularly relevant for disaster preparedness and urban management. Residents in the affected regions—Haryana, Rajasthan, Delhi, Gujarat, Madhya Pradesh, and surrounding areas—are advised to take precautionary measures against cold exposure. Local authorities and state governments may need to enhance cold wave mitigation measures, ensure the availability of heating and shelter facilities, and maintain vigilance for vulnerable populations such as the elderly and children.

Agricultural stakeholders will also need to remain alert. Prolonged periods of low temperatures can damage crops, particularly wheat, pulses, and vegetables. Farmers may need to employ protective measures such as covering crops or adjusting irrigation schedules to counter cold stress.

Looking Ahead

The IMD will continue to monitor the evolving polar vortex and La Niña conditions closely. Updated forecasts and advisories will be issued as the winter season progresses, helping citizens, farmers, and policymakers prepare for potential cold wave events. As OP Sreejith noted, “The forecast is based on a dynamic system. Not many western disturbances are expected over the winter period this time, and La Niña will have a significant impact.”

In summary, the upcoming winter in India is expected to be colder than usual in several regions, with higher than normal cold wave days, below-average minimum temperatures, and mixed rainfall patterns. Citizens are advised to stay informed through official IMD alerts and take necessary precautions to safeguard health, livelihoods, and property during the winter months.