WeatherTalk: Common and regular are misunderstood


In weather and climate, the words “average” and “normal” are terribly misunderstood. An average is the mean over a period of time, usually the recording period. A normal value is similar to the average, except that the data is smoothed to fit on a curve and the time period covered is typically the last full three decades. The problem is, a lot of people get the idea that these averages and normals represent what the weather should be doing, which it isn’t at all.

The weather in general and our climate in particular are extreme. It’s almost always hot, colder, wetter, or drier than average. Average is the average of all extremes. When we experience a warm phase like around Easter or a cold moment like the last few days, the weather actually does what has always been done, which is different from the average.