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Heat Index Calculator

Calculate the heat index (feels like temperature in heat). Find apparent temperature from air temperature and relative humidity.

Actual Temp

32°F

Feels Like

21.6°F

How to Use the Heat Index Calculator

Enter your values above for an instant result. This tool uses verified formulas and is optimised for users in USA, Canada, UK, Australia. All calculations happen in your browser — your data is never sent to our servers.

Frequently Asked Questions

When does heat become dangerous?

A heat index above 103°F (39°C) is dangerous. Above 125°F (52°C) is extreme danger with imminent heat stroke risk.