The Weather-Health Alerting System guidance page was first published by the UK Health Security Agency (UKHSA) on 1 June 2023, setting out how early warnings are issued when adverse temperatures are likely to affect the health and wellbeing of the population1. The system is provided by UKHSA in partnership with the Met Office1.
The guidance states that the system is made up of the Heat-Health Alerts (HHA) and the Cold-Health Alerts (CHA), and that it underpins the Adverse Weather and Health Plan1. The core alerting season for the HHA runs from 1 June to 30 September, and the core alerting season for the CHA runs from 1 November to 31 March1. Should a period of heat or cold occur that meets alerting criteria outside those core periods, an extraordinary alert will be issued1.
The page records that it was updated on 21 June 2024, when links to the "Weather-Health Alerting System" and "Weather-Health Alerting situation" were changed to a new dashboard, and again on 22 April 2026, when a link to the user guide was added1. The same page also records a correction made on 1 June 2023 to the core alerting season dates for the HHA and the CHA1.
"It's intended to provide early warning to the health and social care sector, the responder community, the voluntary and community sector and government departments when adverse temperatures are likely to impact on the health and wellbeing of the population."
| Item | Detail |
|---|---|
| Provided by | UK Health Security Agency, in partnership with the Met Office1 |
| Components | Heat-Health Alerts (HHA) and Cold-Health Alerts (CHA)1 |
| HHA core season | 1 June to 30 September1 |
| CHA core season | 1 November to 31 March1 |
| Outside core seasons | An extraordinary alert will be issued if alerting criteria are met1 |
| Distribution | By email to all those who have registered to receive them1 |
| Supporting document | Weather-Health Alert System user guide1 |
Why it matters for households
The guidance describes the alerting system as aimed at the health and social care sector, the responder community, the voluntary and community sector and government departments, rather than at households directly1. Alerts are distributed by email to all those who have registered to receive them once they are issued, and the page invites people to register and to share the link with anyone they feel should be receiving them1. The page states that a Weather-Health Alert System user guide has been published to help users understand how the information in the alerts can be used when coordinating the response to adverse temperatures, and to give an overview of what each alert colour means in terms of expected impacts on health1. The page also links to current alerts through the UKHSA dashboard1.
For households, the practical effect is that heat alerts fall within a season running from 1 June to 30 September and cold alerts within a season running from 1 November to 31 March, with extraordinary alerts possible outside those periods if conditions meet the criteria1. The staying-informed hub covers how households receive official warnings, and the heatwaves and drought hub covers heat and water scarcity. The Adverse Weather and Health Plan page explains how services respond under the plan that the alerting system underpins1.
What happens next
The page records no further scheduled changes beyond the updates already listed, the most recent dated 22 April 20261. No announcement of any change to the alerting seasons or to the registration arrangements has been reported1.
