sentences:  Since Baháʼí days start at sundown, if the equinox occurs just before sunset, the day which started on the previous sunset is Naw-Rúz.Thus Naw-Rúz could fall on either March 20, 21st or 22nd of the Gregorian calendar, though these dates are pre-calculated years in advance.All dates in the Baháʼí calendar are set in relation to Naw-Rúz and thus may shift on the Gregorian calendar by a day or two depending on the timing of the vernal equinox.