Mark T. Sheehan High SchoolSchool Calendar
2026-27 Academic Calendar
Key dates, holidays, and events for Mark T. Sheehan High School.
School at a Glance
Upcoming events & academic holidays2026-27 Academic Year
AUG
24
Professional Development Day
AUG
25
Professional Development Day
AUG
26
Professional Development Day
AUG
27
First Day of School
SEP
1
First Day of Preschool
SEP
7
No School
Labor Day
SEP
17
Student 2-hour early release
OCT
12
No School
Columbus Day
OCT
15
Student 2-hour early release
OCT
22
Early Dismissal/Conferences
NOV
3
Election Day/Prof. Dev. Day
NOV
11
No School
Veterans' Day
NOV
25
Early Dismissal
NOV
26
No School
Thanksgiving Recess
DEC
10
Student 2-hour early release
DEC
23
Early Dismissal
DEC
24
No School
Holiday Recess
JAN
18
No School
Martin Luther King Day
JAN
21
Student 2-hour early release
FEB
15
No School
Winter Break/Presidents' Day
FEB
25
Student 2-hour early release
MAR
18
Student 2-hour early release
MAR
26
No School
Good Friday
APR
1
Early Release/Conferences
APR
12
No School
Spring Break
APR
22
Student 2-hour early release
MAY
20
Student 2-hour early release
MAY
31
No School
Memorial Day
JUN
9
Potential Last Day
Partner TipEarly dismissal days and parent-teacher conferences are often updated 2 weeks in advance. Check back regularly to stay ahead of the schedule!
Standardized Test Dates
Upcoming national, state, and school calendar dates that affect students at Mark T. Sheehan High School.
National Tests
August 7, 2026
SAT — National
Registration deadline
August 11, 2026
SAT — National
Late registration deadline
August 14, 2026
ACT — National
Registration deadline
August 22, 2026
SAT — National
Test date
August 28, 2026
SAT — National
Registration deadline
September 1, 2026
ACT — National
Late registration deadline
State Assessments
February 1, 2027 – May 28, 2027
Next Generation Science Standards Assessment — NGSS
Testing window
CT
March 1, 2027 – April 30, 2027
Connecticut SAT School Day — ELA & Math
Testing window
CT