Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz)2026 · Date · History · Messages
Jewish calendar sources place the fast on 17 Tammuz and document the postponement when that date falls on Shabbat; the Gregorian date is therefore recalculated from the Hebrew calendar each year.
About Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz)
The Fast of the Seventeenth of Tammuz, also called Shivah Asar B’Tammuz, is a Jewish fast day observed on 17 Tammuz and associated with the beginning of the Three Weeks, a period of mourning in the Jewish calendar.
When 17 Tammuz falls on Shabbat, the fast is postponed to Sunday, 18 Tammuz. In 2026, the observance falls on July 2.
Why Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz) matters
Jewish tradition associates 17 Tammuz with several calamities and uses the day to begin a three-week period of mourning leading toward Tisha B’Av.
Practices and pastoral guidance belong within Jewish communities. Descriptions of the fast should not be turned into individualized medical or religious instructions.
History of Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz)
Chabad’s explanation of 17 Tammuz lists five traditional events associated with the date, including the breaching of Jerusalem’s walls and Moses breaking the Tablets.
The day functions as the opening fast of the Three Weeks in the Jewish calendar.
Chabad documents the recurring calendar rule that when 17 Tammuz occurs on Shabbat, the fast is postponed to the following Sunday.
What the evidence establishes
Confirmed institutional roles and milestones are shown first. Details that could not be established from the reviewed sources are listed separately below.
8 fields not established in reviewed sources
Also known as
Fast of Shiva Asar B’Tammuz, Seventeenth of Tammuz
How to Observe Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz)
If you observe the fast, follow the practice and exemptions taught by your own Jewish community or rabbinic authority.
For personal questions involving illness, pregnancy, medication, eating disorders or other health considerations, seek individualized guidance from an appropriate rabbinic authority and qualified health professional rather than relying on a general observance guide.
Study the historical and religious meaning of the Three Weeks using trustworthy Jewish sources.
If you are not Jewish, learn respectfully without presenting yourself as speaking for Jewish religious practice.
Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz) Facts
The observance falls on 17 Tammuz in the Hebrew calendar.
It marks the beginning of the Three Weeks.
If 17 Tammuz falls on Shabbat, the fast is postponed to Sunday, 18 Tammuz.
Jewish tradition associates the date with five calamities.
There is no single modern campaign founder or government instrument established by the reviewed sources for this ancient religious observance.
Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz) Messages
Wishing those observing the Seventeenth of Tammuz a meaningful day of reflection.
May this day of remembrance be approached with respect for Jewish tradition and community practice.
May the Seventeenth of Tammuz be observed with dignity and care.
Topic and context
What this page does not assume
- Keep the source-defined country, community, organizer or institutional scope; do not silently broaden it.
- Do not treat the title alone as proof of government recognition or public-holiday status.
- Do not add a creator, founding story or origin claim unless the supporting evidence establishes it.
- Faith Context Respect.
Evidence & sources
Sources used across the guide are gathered here. Labels show how each source supports the page, and contextual references are kept separate from primary evidence.
Chabad — Jewish calendar and observance explanation
Chabad — 17 Tammuz 5786 / July 2, 2026 (opens in a new tab)
Official Faith Community
Chabad — Tammuz overview (opens in a new tab)
Official Faith Community
Chabad — The 17th of Tammuz (opens in a new tab)
Official Faith Community
Understand it, compare it, then explore further
Start with the most common factual questions, then compare closely related observances and explore useful connections.
Frequently asked questions
When is Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz)?
17 Tammuz; postponed to 18 Tammuz when 17 Tammuz falls on Shabbat (2 July in 2026) The documented recurrence rule is: 17 Tammuz in the Hebrew calendar; if 17 Tammuz falls on Shabbat, observe the fast on Sunday 18 Tammuz.
Does Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz) fall on the same date every year?
It follows a recurring calendar rule, so the Gregorian date can change from year to year.
Is Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz) an official public holiday?
The reviewed sources verify it within this scope: Judaism / minor fast marking the start of the Three Weeks. That recognition does not by itself make it a statutory public holiday; the site only makes public-holiday claims when reliable evidence explicitly does so.
Who established or recognizes Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz)?
The documented basis is: Jewish calendar sources place the fast on 17 Tammuz and document the postponement when that date falls on Shabbat; the Gregorian date is therefore recalculated from the Hebrew calendar each year.. Supporting evidence includes Chabad — The 17th of Tammuz. The site does not infer a separate creator or founder unless reviewed evidence establishes one.
Is Fast of the Seventeenth of Tammuz (Shivah Asar B’Tammuz) international or country-specific?
No single country is assigned to this observance. Its documented scope is: Judaism / minor fast marking the start of the Three Weeks. Use that scope rather than assuming worldwide or country-specific status.
How is this page verified?
The factual information is checked against reviewed sources, including the date pattern, scope and institutional history. This page was checked on 2026-09-27.
When is the Fast of the Seventeenth of Tammuz?
It is observed on 17 Tammuz in the Hebrew calendar, with a postponement to Sunday, 18 Tammuz when 17 Tammuz falls on Shabbat.
What period does it begin?
It begins the Three Weeks, a period of mourning in the Jewish calendar.
Is the Gregorian date the same every year?
No. The Gregorian date changes because the observance follows the Hebrew calendar.
Does a general observance page decide who should fast?
No. Personal religious and health circumstances should be discussed with appropriate rabbinic and health professionals.