What Frost in Ooty and Cold Nights in Chennai Tell Us About India’s Winter

Imagine waking up to sparkling frost on your balcony grass, or seeing people in South India pulling out sweaters because it dipped below 20°C — something rare for the city’s winter! 

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In the hill town of Ooty, usually known for its misty mornings and cool breezes, winter has arrived with frost blanketing gardens, lawns, and open fields, delighting tourists and locals alike. On some mornings, the ground wears a shiny white coat that feels almost magical. 

In the Indo-Gangetic plains (Delhi, Punjab, Uttar Pradesh), and the valleys of Kashmir, nights have grown dramatically colder, with temperatures in many places dipping well below freezing, even as low as minus 4°C to minus 6°C in parts of the Valley.

Down South in Chennai, a city more familiar with humidity than hoodies, surprised residents with unusually cool nights. Temperatures dipped below what the city typically experiences in December, prompting many to pull out light sweaters earlier than usual. 

Along with Chennai, Bengaluru is also experiencing dense fog and chilly dawns, with visibility dropping dramatically at times as cold air settles near the ground. 

Further in the Northeast, on the outskirts of Shillong, frost made an appearance too, coating fields and rooftops and signalling that winter had arrived. From southern hill stations to coastal cities and the hills of the Northeast, the cold was no longer confined to one region.

Together, these moments tell a larger story, of a winter that is sharper, wider-reaching, and more intense than what many parts of India are used to.

So what exactly is a ‘Cold Wave’?

A cold wave isn’t just a regular winter chill. It’s when temperatures drop much lower than what’s normal for a region at this time of year. 

In plains, we call it a cold wave when minimum temperatures fall to around 10°C or lower, or are a few degrees below the seasonal average. In the hills, the thresholds are even lower. 

In simple terms, it’s winter, but sharper and more widespread — where nights stay icy, fog sticks around longer, and mornings feel unusually cold for the season. 

Why is this happening now?

There’s a mix of natural weather patterns and broader climate factors at work:

1. Bigger wind patterns over the globe

One major influence this year is the La Niña weather pattern in the Pacific Ocean. La Niña changes wind circulation high up in the atmosphere, helping push cool, dry air from the far north deeper into India. This means nights get colder, and cold air spreads more widely across the plains and hills. 

2. Clear skies at night

You’ve probably noticed how clear nights can feel much colder. That’s because clouds act like a blanket — trapping warmth close to the ground. This winter, many places have clear skies at night, so the heat from the ground escapes quickly, letting temperatures fall faster and more steeply after sunset.

3. High-pressure air staying put

Over northwest India, a ‘high-pressure dome’ — a large area of dense, cold air has been sitting in place. This stops warmer air from the oceans from mixing in, and lets the cold air build up over time. 

4. Jet stream changes

The subtropical jet stream, a fast ribbon of wind high in the sky, is dipping farther south than usual this season. When that happens, it acts like a conveyor belt pushing cold winds deeper into central and northern India. 

Some scientists think this kind of jet stream shift may be linked to broader climate patterns like warming in the Arctic.

All of these factors together make this year’s winter colder and longer in many areas than people generally expect, not just a regular winter chill, but a sustained cold spell that reaches far beyond the typical cold zones. 

According to weather forecasts, this pattern is likely to continue into late December and early January, bringing more cold wave days, dense fog in the plains, and sharp night-time cooling across large parts of the country.

What does it mean for people and daily life?

While frost and fog can make for beautiful scenes and cosy moments with tea and warm clothes, there are real impacts too:

Health & comfort

• Sensitive groups (elderly, children, outdoor workers) are more prone to chills, respiratory infections, hypothermia and cold-related health issues.Travel

• Dense fog and low visibility can delay flights, trains and road travel, especially in the north.
  
  

Agriculture

• Sudden temperature dips and frost can stress crops, affecting growth and yields if farmers aren’t prepared.

Lifestyle

• People in cities like Chennai and Bengaluru are pulling out woollens earlier than usual, a reminder that winter can surprise everyone, even outside traditional cold zones.

What does this tell us?

India’s winters are becoming less predictable. Cold waves are intense, lasting longer, and reaching places that once stayed comfortably mild. 

While cold weather itself isn’t new, the scale and spread of these temperature drops point to changing weather patterns influenced by global climate systems and local conditions.

For now, it means adjusting — staying informed, dressing warmly, checking advisories, and looking out for those most vulnerable to the cold. It also means understanding that extreme weather isn’t limited to heatwaves and floods; winter, too, is changing its rules.

As frost melts away each morning and fog slowly lifts, this winter serves as a reminder: weather across India is evolving. The more we understand why it’s happening, the better prepared we are — not just to cope with the cold, but to respond thoughtfully to the seasons ahead.

Sources:

‘India’s Deepening Cold Wave: What’s Driving It, Who It Hurts Most, and How We Must Respond’ By CEED, Published on 4 December 2025.

‘Kashmir continues to reel under intense cold; Srinagar records –4.5°C’ by Kashmir Images, Published on 28 November 2025.

‘Weather: Ooty Freezes At 5.6°C To Become Coldest Hill Station In South; Kodaikanal Shivers At 6.6°C’ by Prakash KL for OneIndia, Published on 15 December 2025.

‘20 degrees Celsius in Chennai as dry weather paves way for temperature dip in TN’ by The New Indian Express, Published on 15 December 2025.