The second wave happens when places that were hit hard initially are hit hard again. This is still the first wave, where places are being hit hard for the first time.
there's a little more to it... the initial peak has to fall by a certain amount, then rise again to a certain level, before it's declared a second wave (there is also a time element but let's make abstraction of that). i've seen different numbers, but many people talk about at least a 50% fall from the peak before you can start talking about a second wave - and in the US, we haven't fallen by that much. from the peak in early april - lets call that 100% - we dipped down to around 75% in late may/early june. since ~15 june, we've been on an upward swing and currently are at 90% of peak. we haven't dipped far enough down to declare the first wave over.
earlier today i came across a great graph showing different country's curves over time, but i can't find it anymore. so instead i'll offer this
NYT graph of the US alone - note how we plateaued around 75%. compare this to the mini-graphs
on this page, specifically those in the "Where new cases are decreasing" section. jordan could say it's had a second and a third wave.
