Watch: Other than constant misery, what is a heat wave?

We all have some intuitive sense of what constitutes a heat wave.
It’s like the meteorological version of Potter Stewart’s “I know it when I see it” approach to jurisprudence.
But what actually constitutes a heat wave?
Officially, it’s when the maximum temperature for five days exceeds the average maximum temperature by nine degrees.
So you’re not wrong to think that a heat wave is when the city feels like an oven. It’s just that there’s some more