Extreme Heat
What risks does extremely hot weather present?
Three of the biggest risks to health during extremely hot conditions are:
- Heat Exhaustion
- Dehydration
- Ultraviolet (UV) Rays
What should my employer be doing?
Employers are duty-bound to ensure, as far as reasonably practicable, the health, safety, and welfare at work of their employees (HASAW Act). They must:
- take all reasonable steps to achieve a temperature as close as possible to comfortable (room temperature alone does not indicate thermal comfort, as individual preferences vary);
- undertake risk assessments to identify hazards in the workplace, including climate change-related hazards such as heatwaves;
- reduce the risk of harm to employees. If conditions change, such as the risk of extreme temperatures, employers should review and update risk assessments accordingly;
- protect staff who are particularly vulnerable to heat, potentially requiring individual risk assessments.
Find out more on the UNISON website, from Your Employer or from NHS Wales.
Key Links
UNISON Guidance Extreme heat at work | UNISON – the public service union
Denbighshire County Council Guidance https://unisondenbighshire.org.uk/wp-content/uploads/2026/06/Hot-Weather-–-Staying-Safe-and-Comfortable-at-Work.pdf
NHS Wales Hot weather – Public Health Wales
