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You do know that once you put up a 'mill there's normally 3 days of no wind
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That's not just Murphy's law.
In the poleward part of the temperate zones the weather systems tend to come by roughly periodically, several days apart. It has to do with downwind propagation of waves in the boundary between the (ant)arctic and temperate zone regions. Three-ish calm days, or a bit more, is typical.
When you're installing a mill you wait for calm and dry weather, so you're not working in the rain or wrestling with big airfoils in strong or gusty winds.
So you put it up at the beginning of a calm period. Then, when you've got it up, and are waiting with bated breath for some wind to make it spin, you get to wait out the remaining days of the calm period before you get to see whether your new mill actually works. B-)
Or at least that's the case if you don't have something that gives you a daily "lake effect" cycle. (Like northern San Jose CA, where the "lake" is S.F. Bay and the "island" is the valleys to the south. Or Altamont Pass in CA, where the "lake" is the Pacific Ocean, the "island" is the Central Valley, and the pass is the notch in a wall of mountains between them. Or my ranch, where the "lake" is Tahoe and the ice caps on the Sierra Nevada mountains, the "island" is the desert portion of Nevada, and Monitor Pass forms the funnel throat.)
In lake effect situations a windmill is the power takeoff on a solar heat engine the size of an appreciable fraction of a continent. B-)