Traditionally, Tisha B’Av, the saddest day of the Jewish calendar, is observed in several ways:
At the end of the afternoon prior to Tisha B’Av, one eats the Se’udah Hamafsekes, a meal of bread, water and a hard-boiled egg dipped in ashes.
Beginning at sundown, one must refrain from consuming food and drink until the following sundown (unless one is ill).
Bathing is prohibited during the fast. One cannot wear leather shoes, makeup or perfume, have sexual relations or study Torah (except for sections dealing with mourning) during this time. Congregants do not wear tallitot at services or don tefillinuntil minchah, afternoon, services. But one is permitted to work and/or smoke on Tisha B’Av.
Mourning customs include sitting on low chairs or the floor until chazot, or midday, and refraining from conducting business. One should also avoid idle chatter.
At night, Eicha, the Book of Lamentations, is read (with some congregations dimming the lights or using candles). Some observant Jews attend bonfire gatherings or lectures during Tisha B’Av. In the morning, kinot, liturgies of prayer and mourning, are read until chazot, which is at 1:12 p.m. this year.
If Tisha B’Av falls on a Shabbat, the observance is pushed ahead to the 10th day of Av.
Tradition holds that the Messiah will be born on Tisha B’Av.