That's the point. Weather patterns are changing, not everything shifting to one specific weather. Not everything is getting hotter. Eg Europe for now is getting warmer, but at least the west and north of Europe can actually expect more cold, rather than more heat, as the gulf stream (bringing hot water north) is slowly getting weaker and will, following current trends, at some point reverse itself. The equatorial areas can in return expect much more heat (and no relief by patterns such as the gulf stream) and will increasingly desertify over the next decades.
Correlation does not always imply causation. We live in a world with imperfect information and each of us has to decide the best course of action based on the evidence available. The phrase “global warming” is just a shorthand way of saying that we are adding massive amounts of the energy to the system controlling weather. When we see weather changing whilst knowing that we’ve added a massive amount of energy to the system then a reasonable person concludes causation. It’s the most likely explanation.