Official Mount Sinai 2025-2026 school calendar with holidays, breaks, PDF, and calendar sync. 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. Dates are manually collected and screened from district-published calendar materials. Printable PDF and Google/Apple Calendar sync options are available below. Updated March 17, 2026.
| Event | Date(s) | Status |
|---|---|---|
| First Day of School | September 2, 2025 (Tue) | School Opens |
| Rosh Hashanah | September 23, 2025 - September 24, 2025 | No School |
| Yom Kippur | October 2, 2025 (Thu) | No School |
| Columbus Day | October 13, 2025 (Mon) | No School |
| Thanksgiving Recess | November 26, 2025 - November 28, 2025 | No School |
| Winter Recess | December 24, 2025 - January 2, 2026 | No School |
| Martin Luther King Jr. | January 19, 2026 (Mon) | No School |
| Midwinter Recess | February 16, 2026 - February 20, 2026 | No School |
| Spring Recess | April 1, 2026 - April 10, 2026 | No School |
| Memorial Day | May 25, 2026 (Mon) | No School |
| Juneteenth | June 19, 2026 (Fri) | No School |
| Last Day of School | June 26, 2026 (Fri) | School Closes |
View the full 2025-2026 school year by month.
Mount Sinai School District is listed here with official 2025-2026 calendar data. The student year starts on Tuesday, September 2, 2025 and ends on Friday, June 26, 2026.
The main multi-day closure blocks are Rosh Hashanah (Tuesday, September 23, 2025 through Wednesday, September 24, 2025), Thanksgiving Recess (Wednesday, November 26, 2025 through Friday, November 28, 2025), Winter Recess (Wednesday, December 24, 2025 through Friday, January 2, 2026), Mid-Winter Recess (Monday, February 16, 2026 through Friday, February 20, 2026), Spring Recess (Wednesday, April 1, 2026 through Friday, April 10, 2026).
Single-day closures and important calendar items include Yom Kippur (Thursday, October 2, 2025), Columbus Day (Monday, October 13, 2025), Veteran's Day (Tuesday, November 11, 2025), Martin Luther King Jr. (Monday, January 19, 2026), Unused Snow Day (If needed) (Friday, May 22, 2026), Memorial Day (Monday, May 25, 2026), Unused Snow Day (If needed) (Tuesday, May 26, 2026), Unused Snow Day (If needed) (Wednesday, May 27, 2026), plus additional dated items in the table below.
Data source & handling: Official calendar from Mount Sinai School District (mtsinai.k12.ny.us). We manually collect and screen dates from district materials, then organize them into key dates, printable PDF, and calendar sync.
Disclaimer: This site is not affiliated with Mount Sinai School District or NYSED. Official calendars can change - always check mtsinai.k12.ny.us before making plans.
Last updated: March 17, 2026