A data-driven push to beat urban boil

Dhaka is set to gain its clearest picture yet of where heat strikes hardest and how rainfall patterns are evolving, a crucial step toward equipping city planners with actionable climate data amid rising urban temperatures and persistent water-logging woes.
The Institute of Water Modeling (IWM) has completed a year-long collection of microclimate data from more than 20 points across the capital, including open spaces, slums, waterbodies, and built-up areas.
The goal is to pinpoint extreme heat islands (EHI) and changing rainfall behaviours that traditional systems fail to detect with sufficient accuracy.
Officials said the data, now under analysis and expected to be finalised by December, promises to provide a much sharper and ground-truthed understanding of Dhaka's climate stress zones.
"The data collected over the past year from more than 20 sites will help stakeholders grasp the on-ground reality and evaluate scenarios far more precisely than before," said a researcher involved in the project.
He noted that while the study may not yield entirely new findings, it will reinforce and validate many assumptions currently guiding urban planning in the face of climate uncertainty.
At present, city-level heat and rainfall data rely largely on Bangladesh Meteorological Department (BMD) records and satellite-based estimates.
But researchers argue these sources are too broad to capture Dhaka's localised temperature surges or flash-flood-prone zones. BMD stations measure weather at select fixed points, while online temperature data often rely on simulated models.
The urgency is growing. Dhaka, which hovered between 32°C and 33°C for much of the past three decades, saw temperatures spike beyond 38°C in April 2024 - a heat wave many described as feeling even more intense than recorded figures.
On May 11 this year, the city logged a record 41.1°C, while Chuadanga topped 42°C. On that day, even by evening, the thermometer still showed 34.4°C in Dhaka.
Rainfall trends have also shifted. The city received up to 83mm of rain in one day this May, while Noakhali was drenched with 196mm in 24 hours due to a depression in the Bay of Bengal.
The IWM study, titled Assessment of Urban Heat Island Effect at City Level in Different City Scenario, is being conducted under the Department of Environment (DoE).
It aims to track how urban geometry - the shape, material, and planning of the city - has changed over time due to both climate change and human activity, leaving many areas increasingly uninhabitable.
Although 30 monitoring devices were initially set up, researchers were able to gather high-quality data from over 20 strategic spots, including Ramna Park, Mirpur, Old Dhaka, and air-conditioned commercial areas in Gulshan.

The sensors tracked temperature changes day and night, beginning in April 2024.
This isn't IWM's first foray into urban heat. In an earlier pilot study on a single north-south road, researchers found surface temperatures as much as 20 to 22 degrees higher than the ambient air temperature, a striking example of how materials and design can amplify heat stress.
The ongoing study aims to better understand the links between extreme heat, rainfall changes, and human-driven urbanisation.
Its findings will feed into Bangladesh's National Adaptation Plan and inform a proposed Heat Action Plan, a framework that could safeguard not only human health but also food systems and urban biodiversity.
Dr Mohammad Rezaul Hasan, who heads IWM's Climate Change and Environment Unit, said the data may finally push planners to prioritise interventions that bring back comfort and resilience to Dhaka's living spaces.
Among the solutions being considered are more greenery, increased open and blue spaces, use of white or reflective surfaces on rooftops, and shifting building orientation toward north-south axes - all measures aimed at cooling the capital's fast-heating concrete jungle.

smunima@yahoo.com