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It's even worse than that, because solar noon is already different from local noon almost always, almost everywhere.

First, you have to be precisely in the middle of a timezone, and not one of those weird timezones that doesn't actually follow the lines of longitude, either. Otherwise you're skewed late or early relative to solar time. Secondly, solar noon even at the precise center of timezones is only local 12:00 on average, because the timing of solar noon vis-a-vis a 24-hour clock fluctuates through the year by up to 18 minutes. Two factors are involved: the Earth's orbit is slightly eccentric, and Earth's axis of rotation isn't precisely perpendicular to the plane of its orbit (http://en.wikipedia.org/wiki/Equation_of_time has details and a graph).

So all the leap seconds do is keep the average local noon, at precise centers of timezones, equal to solar noon.



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