In recent years, there has been a significant shift from threshold-based to impact-based weather alerting systems. This paper evaluates the impact of this transition within the Weather-Health Alerting (WHA) system in England, which is used to notify the health and social care sector about adverse weather events. The evaluation was conducted after the system's first year of operation to assess its effectiveness in supporting emergency planners and frontline health and social care staff.  Findings show that the shift to an impact-based system has been broadly successful. Stakeholders reported that the most valuable component of the new system is the information provided on expected impacts, which has improved the relevance and utility of the alerts. However, the evaluation also identified several minor concerns, particularly around the clarity of distinctions between alert levels and the volume of information included in alerts. These issues may warrant further refinement in future iterations of the system. Overall, this paper situates the findings within the wider context of climate adaptation and public health resilience, highlighting the essential role of clear, actionable alerting systems in mitigating the health impacts of extreme weather.