6 lessons extreme heat taught us in 2025
Extreme heat has become the new normal. From record-breaking temperatures in South Asia and Europe to sustained scorching conditions across the Sahel, extreme heat has emerged as a defining feature of 2025.
What were once isolated periodic heat spells are now longer, more intense, and increasingly detached from traditional seasons.
Extended heat episodes and rising night-time temperatures are erasing the assumption that heat risk is confined to a specific month, region, or time of day. As heat becomes a persistent feature of daily life, governments and communities are being pushed to treat preparedness as more than a seasonal task, now a year-round responsibility.
Recent heat events have also underscored the uneven distribution of risk, with women, older adults, young children facing disproportionate exposure along with outdoor workers, people living in informal housing, and low-income communities. With social equity at its core, effective heat risk governance depends on collaboration between practitioners at both national and local levels, health systems, labor authorities, and communities.
Heat risk is crosscutting; therefore, no single sector or actor can tackle the challenge alone. The lessons below show what has been discovered about extreme heat and what it will take to respond in a world that will not cool down.
Extreme heat has no off-season
Recent research has made it clear that the nature of heat risk is shifting in both time and space. Not only are individual heat waves becoming more intense, but their span is accelerating faster than global warming itself.
This means what were once the longest and rarest heat events are now increasing in frequency and duration. Hotter sustained periods of heat are putting intense strain on every sector, including health systems, agriculture, and infrastructure.
Learn why heatwaves are increasing in duration
Moreover, the spatial extent of heat waves has expanded over past decades, with extreme heat events now affecting larger contiguous areas across seasons and latitudes than in the past. More people and systems are now exposed to the ill effects of extreme heat than ever before. Taken together, these trends signal that extreme heat can no longer be treated as a seasonal or regional anomaly. Instead, heat preparedness must be embedded into year-round planning and risk management across the globe.
Learn why heatwaves are growing in scale
Heat risk cannot be managed in silos
As extreme heat intensifies, the need for coordinated risk governance has become increasingly urgent. Leaders at the 2025 Global Platform for Disaster Risk Reduction (GP2025) emphasized that piecemeal responses are no longer sufficient, and effective heat risk management requires collaboration across sectors of society and governance levels.
Discover how coordinated action reduces heat risk
This "whole-of-society" approach is a core principle of the Extreme Heat Risk Governance Framework and Toolkit, which was developed to help decision makers assess, strengthen, and sustain integrated responses to heat risk. Rather than offering just another checklist, the framework and toolkit point to a more profound shift in how heat risk must be governed.
When institutions coordinate across sectors, share information, and plan together, fragmented responses begin to function as a system. In doing so, collaboration becomes more than a process; it becomes the mechanism through which societies anticipate heat risk earlier, act more coherently, and reduce impacts more effectively.
Explore the new framework for governing extreme heat
There is no heat resilience without equity
Extreme heat does not affect everyone equally, and recent heat events have made these disparities increasingly visible. Women, particularly those working in the informal sector, are often on the front lines of heat exposure, yet they remain underrepresented in decision-making.
These insights are critical for the design of heat responses that reflect real needs on the ground.
By embedding inclusion into heat planning at the foundation, governments can move beyond one-size-fits-all solutions. Together, we can develop resilience strategies that protect those most vulnerable while strengthening outcomes for society as a whole.
Explore how frontline insights inform heat resilience
Heat warnings must become more localized
At the individual level, extreme heat is experienced locally rather than nationally or regionally. High temperatures, exposure, and risk can vary sharply from one neighbourhood to the next, shaped by urban form, housing conditions, access to shade, and night-time cooling.
Many existing heat warning systems remain too broad to capture these differences, issuing alerts that overlook the places where heat is most dangerous. More localized heat warnings, grounded in neighbourhood-level data and social vulnerability, allow authorities to anticipate impacts more precisely and target action where it matters most.
In an era of persistent heat, the effectiveness of early warning will increasingly depend not on broader coverage, but on finer resolution.
Discover how local experiences shape heat action
Heat standards save lives
Among the clearest lessons emerging from recent periods of heat is the life-saving role of enforceable heat standards.
New analysis shows that policies such as mandatory rest breaks, access to shade and water, and clear temperature thresholds for modifying or stopping work can significantly reduce heat-related illness and death. Yet for millions of outdoor and manual workers, these protections remain uneven or entirely absent. Construction workers, agricultural laborers, workers in the gig economy, and informal workers continue to face prolonged exposure with limited safeguards.
Protecting workers is a core question of public health, equity, and inclusive risk governance. Where heat standards are in place and enforced, lives are saved.
Find out how heat affects work environments
Emerging tech may paint a path forward
Emerging technologies are opening new pathways forward for resilience. As extreme heat becomes more persistent and unevenly distributed, new tools are helping reveal impacts that were previously difficult to quantify.
At the 2025 Global Platform for Disaster Risk Reduction, a Swiss-led innovation was demonstrated that advanced "human-centric thermal mapping", using mobile sensors to capture how humans actually feel heat stress throughout cities.
Beyond mapping temperatures, emerging technologies also open new ways to measure the losses associated with extreme heat, from reduced labor productivity and health impacts to stress on infrastructure and services. By making these losses visible, data-driven tools help shift heat from an invisible risk to one that can be more clearly accounted for in planning and investment decisions.
When combined with local knowledge and inclusive governance, tech innovation offers a path forward.
Discover how technology is transforming heat resilience
A new understanding of heat risk
The lessons emerging from 2025 point to a clear shift in our understanding of heat risk. Heat can no longer be treated as episodic, sectoral, or evenly distributed.
Extreme heat is reshaping risk landscapes faster than many systems were designed to respond. It demands year-round preparedness, integrated governance, locally grounded warnings, strong protection for those most exposed, and an explicit focus on end-to-end equity.
The question is no longer whether societies will face extreme heat, but whether they will act early enough, collectively enough, and inclusively enough to reduce its impacts.