# Tag Info

1

In the fixed calendar it happens 7 times in 19 years. The lunar month, according to our tradition (we announce the "molad") in fact is exactly 29 days, 12 hours, 44 minutes and one "chalak", an 18th of a minute, or 42524 minutes + 1 chalak, or 765433 chalakim. (Hey, almost an easy number to remember, isn't that). If we ignore "leap seconds" and we know ...

3

I am assuming that your question refers to the current "fixed" calendar, so it seems that you have numerous answers on that. I wanted to add that historically, this was not always the situation during the time that the Sanhedrin existed and prior to that. I just completed a class on the history and the workings of the Judaic calendar, which you will find ...

2

Jewish leap years don't happen every seven or every four -- they happen as part of a nineteen year cycle. For example, see the answers to this question, about how to tell which year is a Jewish leap year -- I really liked this answer to that question :)

7

The extra Adar happens when there is a leap year -- we add a month to preserve the lunar properties of the calendar. Seven in nineteen years are leap years, so every 2-3 years on average. From Judaism 101: Adar I is added in the 3rd, 6th, 8th, 11th, 14th, 17th and 19th years of the cycle. (Technically it is Adar I (aka Adar Alef) that's the ...

3

Check out my hebcal-js library, the perfect thing you need for this. Include it, and then you can use one of the following snippets: This is only if you will never have dates in Elul (due to a bug): var hebDate = new Hebcal.HDate(new Date(2014, 11 /* meaning 12 */, 8)); hebDate.setMonth(hebDate.getMonth() + 1); var gregDate = hebDate.greg(); // a ...

1

Looking at your example, you can simply take advantage of the date conversion functions built into whichever library you are using. So if you want to add a Hebrew month to a Julian date, you can: Convert the Julian date into a Hebrew date (i.e. Hebrew Year / Month / Day) Take the Hebrew month value and add 1. Just keep in mind that if you are in Elul and ...

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