Winds were howling again on Wednesday and recency bias (like my usage of 'again' just a few words earlier) would seem to indicate it has been windier than average so far this winter season. When measured by average daily average wind speed, the featured chart would seem to indicate otherwise. The chart shows the average wind speed between 1 December and 5 January for Des Moines. There are caveats galore to a chart like this including that "average wind speed" isn't really something directly measured anymore. For the modern period, what we have are hourly or better reports of two minute average wind speed over 2 or 3 second samples. Sound confusing? It gets even worse when considering the change from a more traditional cup anemometer to a two or three dimensional sonic instrument. A first glance at the featured chart would imply that the 1940s and 1950s were windier than today, but again we have to consider changes to how wind speeds were reported back then. Putting aside the long term changes, even looking back just 10-20 years indicate that this season has not been anything exceptional.

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Tags:   wind