Chicago hit the 103-degree heat index level only four times from 1979 to 1998.

从1979年到1998年，芝加哥只有四次达到103华氏度的高温指数。

We've seen index levels literally fly off the charts, and it's supposed to be this way at least through the end of the week.

我们已经看到指数水平暴涨，这种趋势至少延续到本周末。