Bahá'í calendar
Each year starts on "Naw-Rúz", the vernal equinox (in March), and has 19 months. Each month has 19 days. An extra 4 or 5 days are added between the last two months so that the next year also starts on the equinox. Each day begins at sunset. The time of sunset and the time of the equinox are calculated by astronomers.