The Jewish holiday that falls on Monday, September 25 (in the year being referenced by current online calendars) is Yom Kippur , the Day of Atonement.

Quick Scoop: What Jewish holiday is Monday Sept 25?

  • Holiday name: Yom Kippur
  • Type: Holiest day in the Jewish calendar, a major High Holy Day
  • Typical timing: Begins at sundown the evening before (Sunday night) and continues through nightfall on Monday, September 25 in the year in question.
  • Main themes: Atonement, repentance, reflection, seeking forgiveness from God and from other people.

What happens on Yom Kippur?

Many Jewish people:

  • Fast for about 25 hours (no food or drink) as a spiritual discipline.
  • Spend much of the day in synagogue services, with special prayers focused on confession, forgiveness, and renewal.
  • Refrain from work and treat it as a very solemn, introspective day.

In traditional communities, Yom Kippur is so central that calendars, schools, and workplaces often adjust schedules around it.

Why it might be trending or widely noticed

  • It often affects school and work calendars, especially in areas with large Jewish populations.
  • News outlets and community bulletins commonly highlight the dates of the High Holy Days (Rosh Hashanah and Yom Kippur), so “what Jewish holiday is Monday Sept 25” becomes a common search right before it.

In context of the Jewish fall holidays

To see where Yom Kippur sits in the broader fall holiday season:

[3][9] [9][3] [1][5] [1][5] [7][8] [8][7]
Holiday Approx. Gregorian timing (that year) Role in season
Rosh Hashanah Mid–late September, just before Yom KippurJewish New Year, beginning of the High Holy Days
Yom Kippur Evening before through Monday, Sept 25Day of Atonement, climax of the High Holy Days
Sukkot Follows Yom Kippur by a few daysWeek‑long harvest and pilgrimage festival

TL;DR

  • If you’re asking “what Jewish holiday is Monday Sept 25,” you’re almost certainly looking at Yom Kippur , which runs from the prior evening through that Monday.
  • It’s a solemn, fast-day focused on introspection, repentance, and starting the new year spiritually “clean.”

Information gathered from public calendars and explanatory resources available on the internet and portrayed here.