When do Jews fast?

Yom Kippur is a the only Biblical fast day. On Yom Kippur, Jews pray for forgiveness for all their sins. No eating, drinking, bathing, anointing or marital relations are allowed. Wearing leather shoes is also prohibited.

There are also some minor fast days (besides Yom Kippur) that are observed:

  • Tzom Gedalya; the morrow of Rosh Hashana
  • Asara B'Tevet - 10th of the month of Tevet, a week after Hanukkah
  • Ta'anit Esther - the day before Purim
  • Shiva Asar B'Tamuz - 17 of Tamuz
  • Tisha B'Av - 9th of the month of Av

Minor fasts start at dawn and end at nightfall, except for Tisha B'Av which starts at sunset and lasts for 25 hours. The 3 weeks between Shiva Asar B'Tamuz and Tisha B'Av is a period of mourning for the destruction of the Temple, referred to as "the 3 weeks" or Bein Hametzarim. The mourning intensifies during the last 9 days of these 3 weeks.