The Heat Index . . . What's That?
The Heat index (HI) is sometimes referred to as the "apparent Temperature". The HI, given in degrees F, is a measure of how hot it feels when relative humidity (RH) is combined with the actual air temperature.
So if the temperature was 85F and the Relative Humidity was 85% the Heat Index value would be 99F. Believe me, that's an uncomfortable value. Many parts of the country will see heat index values over 100F this summer. Thanks to the invention of air conditioning many are fortunate to keep cool during the heat of summer. For those who do not have air conditioning, it's important to try to keep cool.
NOAA's Weather Prediction Center has created a great “WPC Heat Index Forecast Page” that you can use to determine the heat index forecasted at your particular location. They also have a wonderful “Heat Index Calculator” for you to try out.
Finally here is a list of possible heat disorders that could result for people in high risk groups when the HI reaches a certain value:
Heat Index of 130F or higher = Heat stroke or sunstroke likely.
Heat Index between 105 - 129F = Sunstroke, muscle cramps, and/or heat exhaustion likely. Heatstroke possible with prolonged exposure and/or physical activity.
Heat Index between 90 - 105F = Sunstroke, muscle cramps, and/or heat exhaustion possible with prolonged exposure and/or physical activity.
Heat Index between 80 - 90F = Fatigue possible with prolonged exposure and/or physical activity.
On a final note, pets such as dogs are very susceptible to heat stroke. Don't forget to find a shady, cool spot for your pets, they will be thankful you did.