Many people across Bangladesh are asking the same question this winter: Why does it feel so much colder than usual?
The answer is simple -- this is not just a matter of personal discomfort or coincidence.
Several powerful climate forces, both regional and global, are working together to make this winter sharper and more persistent than what we normally experience.
Bangladesh already experienced a colder-than-average winter in 2024-25, and the current season is showing similar, if not stronger, signs.
According to the Bangladesh Meteorological Department, several cold waves were expected between November and January, with the northern and central regions likely to feel the brunt of it.
For millions of people -- especially those living in rural areas and informal housing -- this colder weather is a serious concern.
One of the main drivers behind the cold is La Niña, a global climate pattern that begins thousands of kilometers away in the Pacific Ocean.
When La Niña is active, it disrupts normal wind and pressure systems around the world. For South Asia, this usually means cooler winters.
The current La Niña, which developed in late 2025, is already influencing weather patterns across the region, lowering temperatures and increasing the likelihood of cold waves in Bangladesh.
Another important factor is the jet stream, a fast-flowing current of air high above the Earth.
Think of it as an invisible river in the sky that helps guide weather systems. This winter, the jet stream has shifted slightly southward, allowing cold air from higher latitudes to travel deeper into northern India.
From there, it easily spreads into Bangladesh. When the jet stream dips sharply, cold air arrives suddenly -- explaining why cold waves can feel intense even if they are short-lived.
The Indian Ocean Dipole, a climate pattern closer to home, is also playing a role.
Currently, it is in a negative phase, which favours cooler conditions across South Asia during the winter.
This ocean-driven imbalance strengthens the flow of cold air into the region and adds to the overall chill being felt across Bangladesh.
Geography further amplifies the effect.
During winter, high-pressure systems develop over northern India and the Himalayan region. These systems push cold, dry air southward.
As this air mass moves across the plains, it reaches Bangladesh, causing temperatures -- especially at night and in the early morning -- to drop sharply.
While the most extreme cold remains farther north, Bangladesh still feels its impact.
In simple terms, Bangladesh is cold right now because:
- La Niña is cooling the regional climate
- The jet stream is bringing cold air farther south
- The Indian Ocean Dipole is supporting cooler conditions
- Cold, dry air from the Himalayas is flowing into the country
Together, these factors explain why this winter feels sharper, longer, and more intense than usual.
What is important to understand is that this cold spell is not an isolated event.
Large parts of the Northern Hemisphere, including regions of the United States and Canada, are also experiencing colder-than-normal winters.
This tells us that Bangladesh’s current cold weather is part of a wider global climate pattern rather than a local anomaly.
As climate variability increases, winters in Bangladesh may become more unpredictable -- sometimes milder, sometimes harsher.
While scientific explanations help us understand why this is happening, they also highlight the need for better preparedness.
Cold waves disproportionately affect the poor, the elderly, and children. Ensuring access to warm clothing, proper shelter, and public awareness is just as important as tracking temperature forecasts.
This winter’s cold is a reminder that climate change does not always mean warming everywhere all the time.
Sometimes, it arrives as biting cold -- and Bangladesh is feeling it now.
Dr Md Rashed Chowdhury is a climate scientist and is currently affiliated with Arizona State University (USA). Email: [email protected].
