Check the live WBGT level near the activity, then adjust duration, intensity, clothing, hydration and breaks for the people involved.
A general low, moderate or high level does not replace judgement about age, health, symptoms and the activity itself.
Use WBGT, not air temperature alone
WBGT combines air temperature, humidity, wind and solar radiation. The same air temperature can produce different heat-stress conditions. Check the nearest current reading rather than relying only on the phone weather icon. (NEA heat stress advisory)
NEA derives levels from a sensor network and the nearest reading may not capture every sheltered, paved or exposed micro-location. Look at shade, surface heat and airflow where the family will actually be.
At higher stress, shorten continuous effort, lower intensity, add rest and choose lighter clothing. Hydration alone does not cancel heat load. Move runs, playground time or outdoor queues to a cooler part of the day when possible.
| Situation | What changes |
|---|---|
| Low WBGT and everyone is well | Proceed with normal hydration and monitoring |
| Moderate WBGT | Reduce intensity, add shade and breaks |
| High WBGT | Postpone or move the activity indoors where practical |
| Anyone develops warning symptoms | Stop, cool the person and seek medical help as needed |
Account for individual risk
Young children, older adults, people who are unwell and those with relevant medical conditions may need a more conservative decision. Use medical advice for specific conditions and medicines rather than a generic online threshold. (Meteorological Service Singapore heat stress map)
Confusion, fainting, severe weakness, worsening dizziness or inability to drink are not signals to push through. Stop the activity, move to a cooler place and seek urgent help for severe symptoms.
Use a 20-minute reminder for water, shade and a simple symptom question during prolonged activity. The interval is a worked planning aid, not an NEA medical prescription; shorten it for more vulnerable people or harder activity.
Example: A 90-minute family outing can be split into three 20-minute activity blocks, two 10-minute shaded breaks and a 10-minute arrival or exit buffer. At moderate or high stress, shorten or cancel rather than preserving the timetable.
Recheck when conditions change
Cloud, wind, location and time can change the WBGT during an outing. Recheck before extending the plan. A low reading at breakfast does not approve a long midday activity.
