"The entire population of the US could comfortably fit into the climatically mild parts." Yeah, well, the entire population of the US could be put in giant war

"The entire population of the US could comfortably fit into the climatically mild parts." Yeah, well, the entire population of the US could be put in giant warehouses, eating in cafeterias and hotbunking the beds in three shifts. But that's no way to live. "Vast areas of the US never get particularly cold in winter or particularly warm in summer." Where are these "vast areas"? Outside of maybe the Pacific Northwest and Hawaii, I can't think of any.