Heat Index Safety Calculator
Heat plus humidity feels hotter than the thermometer shows. Enter the air temperature and relative humidity — the heat index, the safety band and practical guidance appear instantly.
Feels like (heat index)
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Safety band
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Guidance
Enter temperature and humidity to see guidance.
General information only, not medical advice. If you or someone near you shows signs of heat exhaustion or heat stroke (confusion, hot dry skin, fainting), call emergency services immediately.
How to use
- Choose metric or imperial units.
- Enter the current air temperature and relative humidity.
- Read the feels like temperature and follow the guidance for your safety band.
Note: The formula is most accurate at 80°F (27°C) and above. Humidity below 40% reduces the feels like temperature slightly; humidity above 85% pushes it higher. This is an estimate.
Tips
- Drink water before you feel thirsty and rest in shade regularly.
- Outdoor workers should plan the heaviest tasks for cooler morning hours.
- Check on elderly people, children and anyone working alone in the heat.
- Never leave children or pets in a parked vehicle.