When the fast falls out on Sunday, like it does this year, there are certain special halachot that must be observed
We eat the third Sabbath meal (seudah shlishit) like we do on any other Shabbat, including the singing of Sabbath songs. However, we stop eating and drinking before sunset.
It is also fitting not to sing joyous songs after sunset.
We also refrain from washing and anointing ourselves after sunset.
One who relieves himself during bein hashmashot should wash his hands normally.
We remain in our Sabbath clothing, keep our shoes on, and continue to sit on chairs and greet each other until a few minutes after Shabbat ends. Then, we say Baruch ha’mavdil bein kodesh le’chol(Blessed is He Who separates between the holy and the mundane), and take leave of Shabbat.
After Shabbat, we remove our shoes, take off our Sabbath garments, and change into weekday clothes. One should wear clothing that was already worn the previous week, because one may not wear freshly laundered clothing on Tish’a B’Av.
Our custom is to delay Arvit until around fifteen minutes after Shabbat ends, in order to give everyone time to take leave of the Sabbath at home, remove their shoes, change their clothes, and come to the synagogue for Arvit and the reading of Eichah in weekday clothes.
The fast begins immediately after Shabbat, making it is impossible to say havdalah over a cup of wine. Therefore, we postpone saying this form of havdalah until after the fast.
We say Havdalah – Ata Chonantanu – in the Arrvit prayers, after which we are permitted to do work. Some say women should pray Arvit on Saturday night in order to say Ata Chonantanu for Havdalah. Women who do not say Arvitshould say, Baruch ha’mavdil bein Kodesh le’chol, so they are permitted to do work.
One must recite the the blessing Boreh Me’orei Ha’esh on a candle Motza’ei Shabbat. It is customary for the rabbi or Chazzan to recite this blessing in the synagogue before the reading of Eicha after we complete Amida.
The blessing Boreh Minei Besamim is not recited since it is meant for pleasure.
At the end of the fast, before eating or drinking, one must say Havdalah over a cup of wine which and say the two blessings: Al hagefen (on the wine) and HaMavdil (He Who separates). No blessing is made on spices or fire.
A sick person who needs to eat on Tish’a B’Av, must say havdalah over a cup before eating. In such a case, it is proper to use chamar medinah – a distinguished beverage other than wine, preferably something intoxicating, but any ubiquitous drink, like coffee, will do.
If one has no such beverage, he should say Havdalah over grape juice, and if even that is unavailable, he should say Havdalah – be’di’avad – on wine and drink a cheek full (around 40 ml.).
When the fast is over on Sunday night, one may eat meat to break the fast this year.
May all these halachot no longer be halacha l'maaseh because the final Geula will soon come to our community and to all of Klal Yisrael.