What are the restrictions on the 17th of Tammuz?

The 17th of Tammuz (Shiva Asar b'Tammuz) is a communal fast day on which eating and drinking are forbidden from dawn (alot hashachar) until nightfall. It marks the beginning of the Three Weeks (Bein HaMetzarim), a period of national mourning leading up to Tisha B'Av. Beyond fasting, additional mourning restrictions apply throughout this period.

Key Takeaways

The 17th of Tammuz is one of four rabbinic fast days, observed from dawn to nightfall.
Five tragic events occurred on this date, as recorded in the Mishnah.
The fast initiates the Three Weeks, during which progressive mourning restrictions apply.
Unlike Yom Kippur and Tisha B'Av, this fast is mi-derabanan (rabbinic), not Biblical — though it has a Biblical source in Zechariah.
The fast will one day become a day of joy, according to the prophecy of Zechariah.

The Fast Itself

Obligation to Fast

The Shulchan Aruch rules explicitly:

"One is obligated to fast on Tisha B'Av, the 17th of Tammuz, the 3rd of Tishrei, and the 10th of Tevet, because of the evil things that occurred on them." [Shulchan Aruch, Orach Chayim 549:1]

This establishes the 17th of Tammuz as one of four communal fast days ordained by the Rabbis.

Duration of the Fast

Unlike Yom Kippur and Tisha B'Av, which last from sunset to nightfall (approximately 25 hours), the fast of the 17th of Tammuz runs only from dawn (alot hashachar) to nightfall (tzet hakochavim). This shorter duration applies to all four minor fasts.

What Is Forbidden

The primary prohibition is eating and drinking. Unlike Yom Kippur or Tisha B'Av, the minor fasts do NOT include the following restrictions:

Bathing/washing
Wearing leather shoes
Marital relations
Anointing with oils

These additional prohibitions are unique to Tisha B'Av (and Yom Kippur for different reasons).

The Five Tragic Events

The Mishnah Ta'anit records five calamities that occurred on this date:

"Five things happened to our ancestors on the 17th of Tammuz: the Tablets were broken, the Tamid (daily offering) was abolished, the city wall was breached, Apostomos burned the Torah, and an idol was placed in the Sanctuary." [Mishnah Ta'anit 4:6]

These five events span both the First and Second Temple periods, underscoring the day's repeated historical significance.

Megillat Ta'anit also notes: "On the 17th of Tammuz the Tablets were broken, the Tamid ceased, Apostomos burned the Torah, and an idol was set up in the Sanctuary." [Megillat Ta'anit, Adar 20]

The Biblical Source: Zechariah

The fast has a prophetic anchor in Zechariah:

"כֹּה־אָמַר יְהֹוָה צְבָאוֹת צוֹם הָרְבִיעִי וְצוֹם הַחֲמִישִׁי..." "So says the Lord of Hosts: The fast of the fourth [month], the fast of the fifth, the fast of the seventh, and the fast of the tenth shall become for the house of Judah joy and gladness and happy festivals — but love truth and peace." [Zechariah 8:19]

The "fast of the fourth month" refers to the 17th of Tammuz (Tammuz being the fourth month). This verse also contains the remarkable promise that these fast days will one day be transformed into celebrations — in the Messianic era.

The Three Weeks: Additional Mourning Restrictions

The 17th of Tammuz launches the Three Weeks (Bein HaMetzarim, "Between the Straits"), culminating in Tisha B'Av. During this period, the following are generally observed:

No weddings (from the 17th of Tammuz through Tisha B'Av)
No haircuts
No listening to live music (many extend this to recorded music)
No purchasing new clothing that requires a shehecheyanu blessing (some hold from Rosh Chodesh Av)

These restrictions intensify during the Nine Days (1st–9th of Av):

No meat or wine (except on Shabbat)
No laundering clothes
No bathing for pleasure
No swimming

And they reach their peak on Tisha B'Av itself, when the full five afflictions apply.

Priestly Blessing on This Day

An interesting halachic detail: the Rambam rules that Kohanim (priests) perform Birkat Kohanim (the Priestly Blessing) at the Mincha (afternoon) prayer on the 17th of Tammuz and other minor fasts:

"Fast days that do not have a Ne'ilah prayer, such as Tisha B'Av and the 17th of Tammuz — since the Mincha prayer is close to sunset, it appears like Ne'ilah and is therefore not confused with a regular weekday Mincha, and therefore Birkat Kohanim is recited." [Mishneh Torah, Prayer and the Priestly Blessing 14:2]

The Kol Bo echoes this ruling, confirming that Birkat Kohanim at Mincha is appropriate on these fasts precisely because the timing near sunset distinguishes it from an ordinary afternoon service. [Kol Bo 125:3]

Who Is Exempt from Fasting?

Based on standard halachic principles (from sources beyond those retrieved):

Pregnant and nursing women are generally exempt from the minor fasts, though customs vary.
Ill individuals (choleh) are exempt.
Children below bar/bat mitzvah are not obligated.
Unlike Yom Kippur and Tisha B'Av, there is more leniency with minor fasts for those experiencing discomfort.

For personal guidance on fasting, exemptions, or mourning practices during the Three Weeks, consult your local rabbi or posek.