Scorching Dhaka: Why Nighttime Temperatures Refuse to Fall in a City of Concrete

In recent years, residents of Dhaka have found little relief even after sunset. Nights that were once cooler now feel almost as stifling as the day. This growing discomfort is not just a matter of perception—it reflects a deeper environmental phenomenon driven by rapid urbanization, climate change, and poor city planning.

The Urban Heat Island Effect

One of the primary reasons behind Dhaka's rising nighttime temperatures is the urban heat island effect. In densely built areas filled with concrete, asphalt, and glass, surfaces absorb heat throughout the day and slowly release it at night. Unlike natural landscapes, which cool quickly after sunset, urban materials trap heat and keep temperatures elevated.

In Dhaka, where green spaces are shrinking and high-rise buildings are rapidly increasing, this effect is particularly intense. The lack of vegetation means less shade and reduced evapotranspiration—both essential for natural cooling.

Disappearing Water Bodies and Green Spaces

Dhaka once had numerous canals, ponds, and wetlands that helped regulate temperature. Over time, many of these have been filled up for construction. Trees and open spaces have also been sacrificed to accommodate the city's growing population.

Without these natural cooling systems, heat accumulates during the day and lingers through the night. The absence of airflow corridors—blocked by unplanned structures—further prevents heat from dissipating.

Climate Change Amplifies the Problem

Global warming is making an already difficult situation worse. Rising baseline temperatures mean that nights start off warmer than before. Additionally, increased humidity—common in Bangladesh's climate—makes the heat feel even more oppressive, reducing the body's ability to cool itself through sweating.

Irregular weather patterns, including prolonged heatwaves, are becoming more frequent. These changes are consistent with broader trends observed in Bangladesh and across South Asia.

Energy Use and Heat Emissions

Ironically, the increased use of air conditioners to cope with the heat is also contributing to the problem. Air conditioning units release heat into the surrounding environment, especially in densely populated neighborhoods. Vehicles, generators, and industrial activities add to this "waste heat," further raising nighttime temperatures.

Health and Social Impacts

The inability to cool down at night has serious consequences for public health. Poor sleep quality, heat stress, and increased risk of cardiovascular and respiratory problems are becoming more common. Vulnerable populations—such as the elderly, children, and low-income communities—are especially at risk.

For many residents, particularly those living in informal settlements or without access to cooling systems, the nights offer no escape. This constant exposure to heat affects productivity, well-being, and overall quality of life.

What Can Be Done?

Addressing Dhaka's nighttime heat crisis requires both immediate and long-term solutions. Urban planners must prioritize green infrastructure—planting trees, preserving parks, and restoring (water bodies). Building designs should incorporate reflective materials and better ventilation to reduce heat absorption.

Policies to regulate industrial emissions, improve public transport, and promote energy-efficient cooling systems can also help. Community awareness and citizen participation are crucial in preserving whatever natural resources remain.

A City at a Crossroads

Dhaka's rising nighttime temperatures are a warning sign of a city under environmental stress. Without strategic planning and collective action, the situation is likely to worsen in the coming years.

The challenge is clear: to transform Dhaka from a heat-trapping concrete jungle into a livable, climate-resilient city—where nights once again bring relief instead of relentless warmth.