Boston known for its harsh winters, is now facing a new reality sweltering heatwaves. As global temperatures rise due to climate change, the city is experiencing more days above 32°C (90°F) than ever before. While the late 20th century saw around 11 such days annually, estimates suggest this number could rise to 40 by 2030 and a staggering 90 by 2070.
Last year alone, Boston declared two heat emergencies, but researchers say the real picture is far worse. Studies by Patricia Fabian of Boston University reveal that heat levels in certain neighbourhoods are much higher than official readings. Her team found that in Chelsea and East Boston, average temperatures were 3.3°C higher than those recorded at Logan Airport, where the city’s main weather station is located. On some days, peak temperatures were more than 5.6°C higher, meaning some areas reached emergency heat thresholds without official alerts.
Globally, heat stress is the leading cause of weather-related deaths. In cities, the risks multiply due to the urban heat island effect where concrete, asphalt, and reduced vegetation trap heat. Vulnerable groups such as the elderly, low-income residents, and those without cooling access face the highest risk.
Jessica Lee from the National Weather Service acknowledges that weather stations “cannot always perfectly represent the diverse microclimates of surrounding areas.” The service is now exploring ways to refine its heat alerts using more localised data, community input, and urban mapping.
The issue is not limited to Boston. Similar discrepancies have been found in cities like Miami and New Orleans, where neighbourhoods recorded temperatures several degrees higher than official airport stations.
Thousands of miles away, Delhi faces its own urban heat crisis. Between March and June 2024, 733 deaths across India were attributed to heatstroke, with 193 in Delhi alone. Yet, as in Boston, the city official temperature readings taken from the Safdarjung station fail to capture local extremes. Neighbourhoods such as Narela, Najafgarh, and Northeast Delhi, marked by industrial activity, dense housing, and poor ventilation, record much higher temperatures.
Aditya Valiathan Pillai, a heat governance researcher, points out that “the structures of houses in elite neighbourhoods and informal settlements are worlds apart.” While some homes benefit from ventilation and electricity, others trap heat with tin roofs and concrete walls, worsening exposure.
Delhi’s Heat Action Plan, launched in 2023, aims to guide responses to extreme heat, but experts argue it lacks the micro-level detail needed to protect the most vulnerable. The citywide alerts do not reflect how temperature, humidity, and infrastructure combine to create hyperlocal heat pockets.
Pillai emphasises that “heat warnings must be issued with an understanding of more than just temperature.” He adds that communication methods should also vary in poorer areas, for instance, a public loudspeaker might be more effective than an SMS alert.
However, awareness alone is not enough. Many workers in Delhi’s informal sectors have no protection from heat no right to rest breaks or shaded spaces. “Just giving them information when they can’t act on it is pointless,” Pillai says.
In the US, the National Weather Service is working on solutions too. Its HeatRisk tool now translates temperature forecasts into a five-level colour-coded risk system, helping communities gauge local dangers. Efforts are also underway to develop technology that issues neighbourhood-specific heat alerts.
Julia Kumari Drapkin, CEO of ISeeChange, which monitors heat patterns in New Orleans, believes the approach must combine top-down policy with bottom-up participation. Cities, she says, must listen to local experiences to build effective systems.
From Boston to Delhi, one message stands out fighting heat requires not just forecasts, but fairness. As temperatures climb and heatwaves intensify, survival in cities will depend on how well local realities are understood, communicated, and addressed.