Complete school year calendar for Mount Sinai School District, Suffolk County. Includes all holidays, breaks, half days, and important dates from September 2025 through June 2026.
| Event | Date(s) | Status |
|---|---|---|
| First Day of School | September 2, 2025 (Tue) | School Opens |
| Rosh Hashanah | Sep 23–24, 2025 (Tue–Wed) | No School |
| Yom Kippur | Oct 2, 2025 (Thu) | No School |
| Columbus Day | Oct 13, 2025 (Mon) | No School |
| Veterans Day | Nov 11, 2025 (Tue) | No School |
| Thanksgiving Recess | Nov 26–28, 2025 (Wed–Fri) | No School |
| Winter Recess | Dec 24, 2025 – Jan 2, 2026 | No School |
| MLK Day | Jan 19, 2026 (Mon) | No School |
| Mid-Winter Recess | Feb 16–20, 2026 (Mon–Fri) | No School |
| Eid al-Fitr (Supt. Conf. Day) | Mar 20, 2026 (Fri) | No School |
| Spring Recess | Apr 1–10, 2026 (Wed–Fri) | No School |
| Memorial Day | May 25, 2026 (Mon) | No School |
| Juneteenth | Jun 19, 2026 (Fri) | No School |
| Last Day of School | June 26, 2026 (Fri) | School Closes |
Complete month-by-month calendar from September 2025 to June 2026. Every day is color-coded so you can see school days, holidays, and breaks at a glance.
The Mount Sinai School District 2025-2026 school year serves approximately 2,200 students in a highly affluent, rapidly growing coastal enclave on Long Island's North Shore (Suffolk County). It operates distinctly on a single, sprawling, campus-like setting for all its schools.
Mount Sinai is widely recognized for its powerhouse athletics (the Mustangs) and highly competitive academics, creating a heavily booked school calendar. Because all three schools share the same immediate traffic footprint, parents must consult the calendar meticulously to navigate staggered early dismissals and major event parking. The district tightly guards its winter and spring recesses, demanding careful use of snow contingency days to preserve family travel schedules.
For easy reference, use the button at the top of this page to download a free, color-coded printable Mount Sinai school calendar for your fridge or desk.
Data Source: Official Mount Sinai School District calendar publication.
Disclaimer: This website is not affiliated with, endorsed by, or connected to Mount Sinai School District or the New York State Education Department (NYSED). For the most current and official calendar, please visit www.mtsinai.k12.ny.us.
Official calendars can still change. Always confirm updates with the district before making plans.
Last updated: March 17, 2026