How long is a month?

Months (and years) don’t last the same amount of time (neither do days/weeks because of DST, but I think that might be ignorable), so I am just curious how beeminder defines them.

Most saliently, if your goal is to do something X times per month, does the slope of the road adjust up/down slightly every month, or is beeminder using a different static definition of “month”? (and if it is, how long is a month? or a year?)

I’m just curious, this isn’t impacting usability for me at all.

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I doubt it means ‘calendar month’ as in the fluctuating duration of Gregorian calendar months and may be amount desired / 30 to produce a daily rate. The Beeminder tick is daily, afaik.

So by that theory a beeminder month is exactly 30 days.

I’m sure the answer will be posted soon, in the meantime my guess is m_{b} = \frac{365.24}{12}, i.e. an average year in days, divided into twelve equal-sized beeminder months.

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If we’re going to be precise then we should go all the way and use 365.2425.

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shows Do It Yourself or Days In a Year rather, at 365.25.

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Thank you, I just learnt something from the new. I knew about the 4-year rule and the 100-year rule but had never heard of the 400-year rule.

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It’s the 400-year rule that made a nonsense of the Y2K panic over leap year calculations. The exception to the exception made the normal rule apply…

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I was too young to worry about stuff like this in Y2K. And there’s a high likelihood I’ll be too old in 2400 AD. So I must conclude that my set of leap year rules was sufficient for all practical purposes.

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Yeah, 365.25 days is what physicists use, for example in defining a light year, so that’s what we went with! A Beeminder month is 365.25/12 = 30.4375 days.

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Cool, thanks!