The Resultant Cycles

(Make sure to read all posts on Birkat HaChamah here)

As I have mentioned before, Birkat HaChamah cannot be understood completely solely from the Baraita of Brachot 59b. There are Solar and Lunar cycles (of 4 years and 3 years, respectively), as well as the 7 Year Luminary Cycle.

Regarding the 7 Year Luminary Cycle, we do not need any of the cycles given in Pirkei D'Rebbi Eliezer. All we need is a 365.25 day year and a 7 hour cycle, and we obtain a 7 year cycle.

When lining up the 4 year Solar and the 3 year Lunar cycles together, they align once every 12 years.

It should be noted that the hour of the week in which Tekufat Nissan occurs moves forward exactly 24 hours in the week for every 12 years.

That is to say:

• Year 1 Tekufat Nissan is in hour 73
• Year 13 is hour 97
• Year 25 is hour 121
• Year 37 is hour 145
• Year 49 is hour 1
• Year 61 is hour 25
• Year 73 is hour 49

But also:

• Year 1 Tekufat Nissan is in hour 73
• Year 7 is Hour 85
• Year 13 is hour 97
• Year 19 is hour 109

So in a way, every 6 years is a half "day", and every 12 years is a full "day" that have passed.