Shacharit: Tachanun: When Not To Say

Tachanun is related to judgment. Tachanun is NOT said at times of din/judgment:
  • At night,
  • On Tish'a B'Av,
  • In a house of mourning, and
  • Yom Kippur.
Tachanun is also NOT said at times of simcha/happiness:
At mincha before (and certainly not on):
  • Shabbat,
  • Jewish festivals,
  • Rosh Hashana, and
  • Rosh Chodesh.
At any prayer service on:
  • Isru chag (the day after each of the Jewish festivals),
  • Entire month of Nisan.
           Reason   Nisan has more than 15 days that we omit tachanun, and once we omit it for most of the month, we don't say it at all.
  • All of Chanuka, Purim, Shushan Purim, Tu B'Shvat, Rosh Chodesh, and from Rosh Chodesh Sivan until the day after Shavuot.
  • Tishrei from shacharit before Yom Kippur until after Simchat Torah (Shmini Atzeret in Eretz Yisrael). Resume saying tachanun:
    • Second day of Cheshvan, or
    • Day after isru chag of Simchat Torah (this is the more prevalent custom among Ashkenazim). Each person should follow his or her family or community custom.
Any time these people are present in your minyan (or in any other minyan in the building) either before a circumcision or while still involved in the brit or meal:
  • Mohel,
  • Sandak, or
  • Father of a boy having his circumcision.
       Note This even applies to mincha if the brit will take place after mincha.
 
Any time a groom is present during the first week after marriage.