Sat Thai Day occurs at the end of Thai lunar calendar Moon 10, that is, waning day 15, evening (วันแรม ๑๕ ค่ำ เดือน ๑๐). This is a New Moon and so is a Buddhist Sabbath; but not one of the Special Sabbaths, and not one of the secular public holidays in Thailand. It occurs midway past the traditional Thai New Year and near the autumnal equinox. It an occasion for making merit by honoring (บูชา buucha) the spirits of the season, as well as one's deceased relatives, according to local tradition, with various rites and ceremonies.