Tzom Tammuzצוֹם י״ז בְּתַמּוּז

The Seventeenth of Tammuz (Hebrew: שבעה עשר בתמוז‎, Shiv’ah Asar b’Tammuz) is a Jewish fast day commemorating the breach of the walls of Jerusalem before the destruction of the Second Temple. It falls on the 17th day of the Hebrew month of Tammuz and marks the beginning of the three-week mourning period leading up to Tisha B’Av. Like other minor fasts, Tzom Tammuz begins at dawn (first light) and ends at nightfall (full dark). If the 17th of Tammuz falls on a Shabbat, the fast is instead observed the next day, the 18th of Tammuz (on Sunday). Tzom Tammuz carries layered themes of communal loss and repentance. The Mishnah (Ta'anit 4:6) teaches that five calamities befell the Jewish people on this date: Moses shattered the Two Tablets upon seeing the Golden Calf; the daily tamid offering ceased during the Babylonian siege for lack of sheep; the walls of Jerusalem were breached during the Roman siege; the officer Apostomus burned a Torah scroll; and an idol was erected in the Temple sanctuary. Gathering these tragedies onto one day, the fast frames the destruction of the Temple not as a single moment but as a chain of spiritual and national decline. As the opening of Bein ha-Metzarim ("Between the Straits," the Three Weeks), the day turns the calendar toward mourning while also inviting introspection and a return to communal responsibility.

Tzom Tammuz falls on the 17th of Tammuz, the fourth month of the Hebrew calendar, typically landing in late June or July of the secular calendar. As a "minor" fast, it is observed for a single day from dawn (alot hashachar, first light) until nightfall (tzeit hakochavim, full dark), in contrast to the major fasts of Tisha B'Av and Yom Kippur, which run from sunset through nightfall the following day. When the 17th of Tammuz coincides with Shabbat, the fast is deferred (nidcheh) to the next day, Sunday the 18th of Tammuz, since public fasting is not permitted on Shabbat. The fast itself is observed the same way in Israel and the Diaspora; the chief difference is liturgical and tied to rite rather than to location (see readings).

The Torah reading for Tzom Tammuz is Exodus 32:11-14 and 34:1-10, the passage known as "Vayechal Moshe," which is the standard reading shared by all minor public fast days. It is read at both Shacharit (morning) and Mincha (afternoon), provided a minyan is present with at least three people who are fasting. In the Ashkenazic custom, a Haftarah, Isaiah 55:6-56:8 ("Dirshu Hashem b'himatzo"), is added after the Mincha Torah reading; most Sephardic rites do not read a Haftarah on minor fast days. Unlike Tisha B'Av, which has its own distinctive mournful Eicha (Lamentations) trope, Tzom Tammuz has no special melody: the Torah portion is chanted in the ordinary weekday cantillation (taamei hamikra) and the Haftarah in the standard Haftarah trope.

The central observance is fasting, abstaining from all food and drink, from dawn to nightfall; because this is a lighter "minor" fast, those with health needs, pregnant or nursing women, and children are generally exempt. In the liturgy, Selichot (penitential prayers) are added to the morning service, and the "Aneinu" paragraph is inserted into the Amidah, recited by the prayer leader in the repetition and by individual fasters within the Shema Koleinu blessing at Mincha. Many give tzedakah (charity) before the afternoon service, echoing the Haftarah's call to keep justice and do righteousness. The day also opens the Three Weeks (Bein ha-Metzarim), during which Ashkenazic custom is to refrain from weddings, live music and public celebrations, and haircuts, a mourning period that intensifies as it builds toward Tisha B'Av. Specific customs and exemptions can vary by community and movement, so practice may differ.