What is normal weather?

One doesn?t spend much time learning about climatology before coming across a marvelous sound bite: ?Climate is what you expect, weather is what you get.? The catch is it?s not clear how to measure what you expect. We?re a lot better at measuring weather.

The whole topic of measuring expectations deserves its own web page, as does the problem that we humans are pretty terrible at remembering weather, even extreme weather, and sometimes even recognizing extreme weather.

One way we define ?normal? is that every ten years climatologists collect and average the previous thirty years of weather data, then release that as the ?new normals.? While that has a lot of shortcomings, and some are mentioned below, it all works out pretty well when comparing the ?current normals? to the ?current weather.? However, when new normals are released, and are different than the old…