Cities are arranged left to right according to highest average annual temperature. The relative temperature and precipitation levels are based on monthly averages, while the wind indicators show annual (not monthly) average wind speed. Watch as the Bridgetown and Reykjavik wind arrows fly by relative to the barely moving Los Angeles breeze. You can hover over a city's circular lane to highlight it. Don't see any arrows? Wait a few seconds, and they'll come back around.
Some interesting things you might notice: Chicago is indeed a "Windy City," but not to any extraordinary degree. In fact, Boston is windier. San Francisco is all the way towards the right, because on average it never reaches higher temperatures than the Scandinavian cities at their hottest. London is not very rainy, while Tokyo gets more than a fair share. Nowhere gets rainier than Lagos.
The Weather Wheel is based on widely available weather data, but does not display the actual numbers. Things like millimeter precipitation readings are not very meaningful to most people, so thinking of and showing these metrics in a relative way instead seemed like a clean and elegant approach. It should also avoid upsetting anyone trying to make a living selling this kind of data...
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