Chahrshanbeh Souri is on the last Tuesday night of the Persian solar year .
Chahrshanbeh Souri means Wednesday Feast ( the-last-Tuesday night -of-the-persian-solar-year ) , from the word sour which means feast in Persian , or more plausibly , consider sūr to be a variant of sorkh ( red ) and take it to refer either to the fire itself or to the ruddiness ( sorkhī ) , meaning good health or ripeness , supposedly obtained by jumping over it , is an ancient Iranian festival dating back to at least 1700 BCE of the early Zoroastrian era .