Why does the date for the prayer for rain change from one century to the next?
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My due diligence: Praying for rain in the Diaspora How to calculate 60 days from tekufat tishri for any given year? On which evening should we start saying “V'tein tal u'matar li'vrachah”? I see that I’m walking into a “duplicate question” minefield. So if you’ve got an answer, answer quickly. Suppose that we use the word “summer” to refer to that part of the year when the northern hemisphere has relatively warm weather, long days and short nights; and we use the word “winter” by contrast to mean that part of the year when the northern hemisphere has relatively cold weather, short days and long nights. If we do all of that math described in all of those previous questions and conclude that in one century we will begin to pray for rain on December 3, and in the next century we will begin on Decemb...