In the sweltering summer heat, prolonged exposure to the sun can easily lead to heatstroke. The Labour Department recently released new Guidance Notes on Prevention of Heat Stroke at Work, based on the Observatory's Hong Kong Heat Index. These include amber, red, and black-level warnings, outlining rest arrangements for outdoor workers under each warning level. For outdoor workers, the critical question is whether these new guidance notes can ensure their health. The guidelines also categorize labour intensity into light, moderate, heavy, and very heavy physical workload, but do workers know which category they fall into? Meanwhile, what challenges do employers face in implementing these guidelines, and are there criminal liabilities for employers who fail to provide rest periods as stipulated? The increasingly common high temperatures and heatwaves are linked to climate change. Facing extreme heat, we must adopt strategies to adapt and also try to mitigate climate change from various angles.