mean temps have no real connection to extreme highs, during the summer mean temps are mostly driven by elevated mins, we have the same thing going on here.
I can prove this, we have seen an overgrowth of foliage with the wetter climate we have been in. This isn't merely about them neglecting trimming the foliage, it's about this kind of overgrowth not being in existence in the 1930s-1950s when we had many more extremely hot days and a much drier climate. The pictures you posted prove it-- during that earlier era we did not have as much foliage as we have now in our parks and that's because it was much drier back then, which is also why the extreme heat was much hotter
Sure, the places you listed just now are hotter, but it's because they exist in an artificial concrete climate without much in the way of trees. Coast or no coast, there is no way we would EVER match the extreme heat of the 1930s-1950s except for brief intervals like the 1990s and the early 2010s, unless we switch back to a much drier climate.