As a late-summer heat wave hits Ohio, use this heat index chart to see how hot it feels outside.

As a late-summer heat wave hits Ohio, use this heat index chart to see how hot it feels outside.

Heat index chart measuring the air temperatures and relative humidity to produce an apparent temperature.

Residents can use the NWS Heat Index Calculator to calculate what the heat index is locally. In addition, there is the Heat Index Chart with a wider range of temperatures and humidity percentages.