That's interesting. What a big difference too.
All I know is that the Pacific provides good nighttime skip to make many California stations boom in here from more than 2,400 miles, a lot stronger than I used to get any of the big New York stations in Tampa at night from 1,000 miles.
But much of that skip path was on land too.
When I was in St. Thomas on our family vacation in 1973, I liked to hear WABC at night but I don't recall it coming in nearly as steady and strong as stations like KMJ, KFI, and KNX come in here in Hawaii.
Even KGO is a regular, though not always listenable, and they don't send much power this way.