Warmer days, fewer cold spells: Why Delhi's winter felt hotter this time

As winter in New Delhi draws to a close, the city’s skies have become clearer. However, the season, typically known for its biting cold waves, has been remarkably mild this year. Temperatures have remained significantly above normal, leaving residents without the familiar winter chill they usually expect.

 

In fact, the capital has witnessed unusually high temperatures throughout the winter months. October 2024 recorded the highest temperatures in over seven decades, while November was the warmest in eight years. December also saw above-average temperatures in the first half of the month. This trend continued into January 2025, which became the warmest January in eight years. February has followed suit, with a maximum temperature of 29.7 degrees Celsius recorded on February 13 — six degrees above the seasonal norm — according to the India Meteorological Department (IMD).

 

 

A winter without cold waves

 

Cold waves, a defining characteristic of Delhi’s winters, were almost entirely absent this season. December recorded just one cold wave day — the only such occurrence this winter. Safdarjung, the city’s main weather station, did not register any cold wave events, though some parts of Delhi did experience isolated instances of cold wave conditions.

 

What exactly is a ‘Cold Wave Day’?

 

A cold wave day is marked by a significantly lower-than-usual maximum temperature. However, this winter lacked the prolonged dips in minimum temperatures that typically define cold wave conditions. The IMD attributes the unseasonal warmth in Delhi and across northwest India to weak western disturbances, which usually drive temperature drops during the winter months.

 

Reasons behind the warmer winter

 

IMD Director General Mrutyunjay Mohapatra told The Financial Express that the lack of strong western disturbances played a crucial role in this season’s warmer temperatures. These weather systems typically bring cold air from the northwest, resulting in temperature declines and cold wave events. However, this winter, these disturbances were weaker than usual, leading to minimal rainfall and snowfall in the Himalayan region — factors that usually contribute to maintaining colder temperatures.

 

Additionally, the absence of persistent northwesterly winds, which normally carry cold air from the mountains, allowed clear skies to dominate. With fewer clouds and minimal rainfall, the sun’s radiation directly heated the surface, further raising temperatures. In most winters, cloud cover and rain act as natural insulators, helping to keep temperatures in check, but this season’s dry conditions amplified the warmth.

 

Another contributing factor was the absence of La Nina, a climatic phenomenon that generally brings colder weather to northern India. Though La Nina conditions were expected to develop in December, they did not materialise, further reinforcing the unusual warmth.

 

Deficient rainfall and its impact

 

According to IMD data, October and November saw almost no rainfall, recording a 100 per cent deficit in both months. December did bring some relief, with 53.8 mm of rainfall — making it the wettest December in 27 years. However, most of this precipitation was concentrated on a single day, December 28, which saw 41.2 mm of rain — the highest single-day total in 101 years. While this temporarily lowered temperatures, it had little long-term impact on the season’s overall warmth.

 

January, in contrast, faced another rainfall deficit, receiving only 6.6 mm against the expected 19.1 mm — a 65 per cent shortfall. Unlike January 2024, which recorded five cold wave days and five cold days, January 2025 experienced none, allowing unseasonably warm conditions to persist.

 

February, usually among the coldest months in Delhi, has continued this warm trend. The city received just 0.5 mm of rainfall on February 4, and temperatures have consistently remained above average, extending the season’s unusual warmth.

 

A stark contrast to previous winters

 

Compared to last year’s winter, which saw multiple cold waves and significantly lower temperatures, this season has been markedly different. In 2024, Delhi recorded five cold wave days — the highest since 2012-13 — with a minimum temperature of 4.5 degrees Celsius, which was still the highest minimum recorded in 15 years.

 

This winter’s persistent warmth highlights a distinct shift in seasonal patterns, influenced by weakened weather systems and climate variability. With the season coming to an end, Delhiites have experienced an exceptionally mild winter, raising questions about the long-term trends shaping the region’s climate.