is
Returns if true if tonight is the first night to start reciting Vesein Tal Umatar Livracha ( Sheailas Geshamim). In Israel this is the 7th day of Marcheshvan (so the 6th will return true). Outside Israel recitation starts on the evening of December 4th (or 5th if it is the year before a civil leap year) in the 21st century and shifts a day forward every century not evenly divisible by 400. Vesein tal umatar is not recited on Shabbos and the start date will be delayed a day when the start day is on a Shabbos (this can only occur out of Israel).
Return
true if it is the first Jewish day (starting the prior evening of reciting Vesein Tal Umatar Livracha (Sheailas Geshamim).
Parameters
jewish
the Jewish calendar day.
See also
TODO seems like these can be dried up