England’s groundbreaking transition to an impact-based weather-health alert system is already demonstrating significant promise, according to recent research led by the University of Surrey. By shifting away from fixed temperature thresholds and instead focusing on the likely impacts of extreme weather events on health and services, the new system marks a pivotal advancement in public health preparedness. This evaluation, grounded in direct feedback from a broad spectrum of emergency planners and frontline service providers, reveals that while the system is effective and well-received, there remain areas ripe for refinement to better protect vulnerable populations.
In the summer of 2024, England faced four intense heatwaves, resulting in over 1,300 deaths linked directly to extreme heat exposure. In contrast, the cold winter of 2022/23 saw more than 5,500 deaths associated with cold weather conditions. These sobering statistics underscore the critical need for timely and actionable weather-health alerts. The new Weather Health Alert (WHA) system, developed collaboratively by the UK Health Security Agency (UKHSA) and the Met Office, encapsulates this need by integrating meteorological data with health risk assessments to provide more nuanced and practical warnings than ever before.
At the core of the WHA system is a color-coded alert framework—yellow, amber, and red—which synthesizes both the severity and probability of weather impacts. Yellow alerts typically denote potential effects on vulnerable individuals or localized services, positioning responders to take preventative measures before issues escalate. Amber warnings signify more widespread and serious consequences necessitating coordinated action across multiple agencies. The red alert represents the highest tier, reserved for extreme conditions demanding immediate and robust intervention to safeguard public health. This stratified approach enables a scalable response tailored to the evolving risk landscape.
Complementing the color codes, each alert carries a numerical risk score, providing an additional quantitative measure of risk intensity within each category. This dual signaling system enhances clarity and aids decision-makers in prioritizing responses across varied scenarios. The integration of health impact considerations alongside traditional meteorological forecasting represents a transformative evolution in how weather warnings are communicated and operationalized within health and emergency sectors.
The University of Surrey’s Institute for Sustainability undertook a comprehensive evaluation of this first year of operation. Their methodology involved a series of online workshops engaging 93 stakeholders spanning local authorities, NHS trusts, central government entities, and frontline service organizations. Follow-up interviews deepened insights into user experience and system functionality. The engagement underscored broad satisfaction with the system’s conceptual design and practical impact, highlighting its utility in improving readiness and resource allocation.
Emergency planners particularly valued the system’s emphasis on health impacts rather than solely temperature thresholds. This paradigm shift empowers health and social care sectors to anticipate demands more effectively and tailor interventions to protect those most at risk, such as the elderly, young children, and individuals with chronic conditions. The impact-based alerts facilitate proactive hospital and care center preparations, ensuring that surge capacities and emergency protocols are aligned with expected environmental stressors.
Despite these successes, the evaluation identified challenges, especially around the yellow alert category. The gradations within this alert level (risk score levels 7–11) were sometimes not intuitively clear, causing uncertainty about whether escalated actions were warranted when alerts were upgraded. This ambiguity occasionally led to confusion among frontline staff, who found the alert texts dense and difficult to translate rapidly into operational measures during emergencies.
The feedback suggests potential system enhancements such as a tiered communication approach: a streamlined, simplified alert digest for frontline responders complemented by more detailed guidance materials for planners and coordinators. This bifurcated strategy could enable rapid situational awareness on the ground while preserving the necessary depth of information for strategic decision-making at higher operational levels.
Stakeholders also noted the benefit of fewer false alarms under the new system, helping to mitigate alert fatigue—a common issue in emergency communications. Better interagency coordination, fostered by shared situational frameworks, has been another positive outcome, enabling more synchronized responses across health, social care, and voluntary sectors. These developments enhance overall system resilience, a crucial factor in an era marked by increasingly frequent and severe weather extremes due to climate change.
Dr Thomas Roberts, co-author of the study and Co-Director of the Institute for Sustainability at the University of Surrey, emphasized the system’s critical role in modern health and care infrastructure. He remarked, “Extreme weather is now the norm, and so swift and effective warnings delivering consistent action to protect the population are essential tools.” His insights reinforce the value of impact-based alerts as a pragmatic means to safeguard public health amid changing climatic realities.
Dr Ross Thompson from UKHSA underlined the collaborative ethos behind the system, noting the integration of trusted forecasting with health risk intelligence as foundational to its early success. The iterative approach, built on stakeholder feedback, positions the WHA system as a continuously evolving tool aligned with other national warning services, aiming for harmonized communication and optimized response.
Co-author Haeyoung Eun highlighted the system’s potential to revolutionize frontline and population-level responses. By facilitating better heatwave planning and safer care during cold spells, the system fosters resilience and reduces population shocks during extreme events. Addressing remaining ambiguities in the color-coded alerts will be key to unlocking further health benefits in future summers and winters.
This pioneering initiative aligns closely with several United Nations Sustainable Development Goals, including good health and wellbeing, resilient infrastructure, sustainable communities, and climate action. Through this lens, the WHA system exemplifies how integrated scientific innovation and policy implementation can advance public health in the context of escalating climate challenges.
For those seeking deeper insights into the mechanisms and impacts of the new system, the University of Surrey’s Sustainability Innovation Hub provides comprehensive resources and ongoing case studies documenting this transformative approach to weather-health alerting.
Subject of Research:
Article Title: The transition to an impact-based weather-health alerting system in England: An evaluation of stakeholder perspectives
News Publication Date: 1-Oct-2025
Web References: https://www.sciencedirect.com/science/article/pii/S1462901125002059?via%3Dihub
References: 10.1016/j.envsci.2025.104189
Image Credits: Credit: University of Surrey
Keywords: Weather forecasting, Weather, Meteorology, Atmospheric science
