Heat and humidity questions
Not medical advice
These answers explain the weather measures on this site and point to official heat-health guidance. No environmental index can diagnose illness or promise safe conditions for an individual.
Which reading answers my question?
Is heat index the same as temperature?
No. Air temperature is a thermometer reading; heat index combines it with relative humidity to describe apparent heat under shade and light-wind assumptions.
Is wet bulb the same as WBGT?
No. Wet-bulb temperature concerns evaporative cooling. WBGT uses a natural wet-bulb reading together with globe temperature, and dry-bulb temperature for sun exposure.
Can I find the current heat index at my location here?
This site uses the values you enter. It does not retrieve your location or a live forecast. Consult your local weather authority for current conditions and warnings.
What can the result miss?
Can a low result mean there is no risk?
No. Workload, clothing, health, acclimatization, radiant heat and local conditions can increase risk. OSHA cautions against relying on heat index alone for worksite assessment.
Why does a weather app disagree?
It may use another observation time, location or “feels like” method. Check temperature units and whether humidity is entered as a percentage.
Does the calculator set school or sports rules?
No. Follow the current plan and measurements required by the organization responsible for the activity. A web estimate does not override that policy.
Recognize symptoms and get help
CDC/NIOSH lists headache, nausea, dizziness, weakness, thirst and heavy sweating among heat-exhaustion symptoms. Stop the activity, move out of the heat and seek medical evaluation. Do not use a calculator result to dismiss symptoms.
Confusion, slurred speech, seizures or loss of consciousness can indicate heat stroke, a medical emergency. A person with heat stroke may have hot, dry skin or may still be sweating. In the United States, call 911, move the person to a cooler area and begin rapid cooling while help is on the way. Stay with them. Elsewhere, use the local emergency number. Follow the emergency dispatcher's instructions.
For prevention, CDC recommends staying cool, staying hydrated and knowing the symptoms. People with health conditions or questions about medicines should discuss a heat plan with their healthcare professional rather than changing treatment themselves.
Method and transparency
Last updated: 6 November 2026. Not medical advice.