Outdoor and hot work: heat warnings, risk assessment and rest arrangements

Before you start

LD's Heat Stress at Work Warning uses Amber, Red and Black levels and differs from the Observatory's Very Hot Weather Warning. Its issuing mechanism was enhanced again from 28 August 2026, including adjustments for the Extremely Hot Weather Special Alert and abnormal high temperatures. Employers still need a task-specific assessment covering physical effort, sun exposure, humidity, clothing or protective equipment, ventilation and acclimatisation. A warning does not replace assessment of the actual workplace. Use the current LD guidance and applicable rest-time assessment rather than a universal break rule copied from another trade.

What to do, step by step

1. Before starting, assess the workload, environment, protective clothing and acclimatisation needs. Have the supervisor arrange drinking water, shade, ventilation and rest, identifying who can change the task or schedule when conditions worsen.
2. Check the current LD warning and guidance. Adjust timing, rotation and rest for the site-specific risk, recording what was agreed so employees know the practical arrangement rather than only the warning colour.
3. Encourage workers to notice problems and report feeling unwell immediately. Stop the exposure and obtain help; use 999 for an emergency rather than requiring the person to finish a delivery or work stage first.
4. Reassess when conditions or tasks change. A new worker, returning employee or change to heavier protective equipment may need different arrangements; confirm the revised plan and emergency contact with everyone involved.

Costs, timing, and things to check

Recommended rest depends on work intensity and cooling measures. One temperature reading, or cancellation of a warning, does not establish that every indoor or outdoor workplace is safe.

Water or a fan alone is not a complete arrangement. Ensure the agreed rest and cooler area are actually available; approach LD for clarification of occupational-safety concerns or disputed arrangements.

A practical example

A delivery worker handles heavy loads outdoors in the morning and packs goods indoors later. The tasks need separate assessment of exertion, sun exposure and warehouse ventilation. The supervisor moves heavy handling to a cooler period where possible and agrees water and rest arrangements, then reviews them if the warning changes instead of waiting for someone to become unwell.