Shabbat HaChodesh
Begins at sundown on Friday, 20 March 2020 (25th of Adar, 5780)
Shabbat HaChodesh (“Sabbath [of the] month” שבת החודש) precedes the first of the Hebrew month of Nisan during which Passover is celebrated. Exodus 12:1-20 and the laws of Passover. On the first day of Nisan, G-d presented the first commandment of how to “sanctify the new moon” (kiddush hachodesh) for the onset of Rosh Chodesh and thus Nisan becomes the first month of the Jewish year (counting by months.).
Source hebcal