CAIF

"Rosh HaShanah is the Jewish New Year. The biblical name for this holiday is Yom Teruah, literally "day of shouting or blasting." It is the first of the Jewish High Holy Days, as specified by Leviticus 23:23–25, that occur in the late summer/early autumn of the Northern Hemisphere". Wikipedia

It is interesting that both Jews and Muslims use a lunar calendar for holidays (though they are different lunar calendars than each other) instead of the Gregorian calendar we may be used to using in day to day life. This means that holidays shift compared to the Gregorian calendar dates instead of being on a fixed date like Christmas is always on the 25th of December of the Gregorian calendar. So RoshHashanah moves for example ,and so does Ramadan.

Happy New Year to all our Jewish friends celebrating!