Why the heat index matters more than the temperature in this heat wave

(CNN)Checking the temperature reading during this weekend’s heat wave won’t tell the whole sweltering story. It’s going to feel a lot hotter. So, Chicago — with a predicted temperature Friday of 98 degrees Fahrenheit and relative humidity of 58% — can expect it to feel like 118 degrees, she said. And Washington’s forecast temperature of 98 degrees, with relative humidity of 45%, will make it feel like 109. And that’s not even in the sun. “When we, as meteorologists, forecast the high temperatures or the heat index, that is in the shade,” Brink said. “The sun definitely makes it worse.” In “direct sunlight, the heat index value can be increased by up to 15 degrees Fahrenheit,” according to the National …