SchoolDates
Read from the district on October 8, 2026

Cook County ISD 166 school calendar, 2026–2027

Key dates for 2026–2027: first day of school September 8; fall break October 15–16; Thanksgiving break November 26; winter break December 23 to January 1; spring break March 24–26; last day of school May 26.

Next time off Oct 15 Fall break · October 15–16 As of October 8, 2026, the day this calendar was read
School days off this year 17 across 7 separate closures
Last day of school May 26 Wednesday
First day of school September 8; Fall break October 15–16; Thanksgiving break November 26; Winter break December 23 to January 1; Spring break March 24–26; Last day of school May 26;
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Month by month

Days off: school breaks, holidays and staff days. Not days off: early releases and term milestones.

August 2026

SMTWTFS
26
27
28
29
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
4
5
  • 31 onStaff day

September 2026

SMTWTFS
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1
2
3
  • to 3Staff day
  • 7Labor Day
  • 8First day
  • 10First day for some grades

October 2026

SMTWTFS
27
28
29
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
  • 6Testing
  • 15–16Fall break
  • 17Testing

November 2026

SMTWTFS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1
2
3
4
5
  • 7Testing
  • 9Early release
  • 26Thanksgiving break

December 2026

SMTWTFS
29
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
  • 23 onWinter break

January 2027

SMTWTFS
27
28
29
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
4
5
6
  • to 1Winter break
  • 18Staff day

February 2027

SMTWTFS
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
1
2
3
4
5
6
  • 15Staff day

March 2027

SMTWTFS
28
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
  • 6Testing
  • 8Early release
  • 24–26Spring break

April 2027

SMTWTFS
28
29
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1
  • 10Testing
  • 19Staff day

May 2027

SMTWTFS
25
26
27
28
29
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
4
5
  • 22Graduation
  • 26Last day
  • 27Staff day

June 2027

SMTWTFS
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1
2
3
  • 12Testing
School break Holiday, no school Staff day, no students Early release Term milestone

Key dates

Key dates · 2026–2027
WhatDatesSchool daysBack to schoolSame dates in Minnesota
First day of schoolSeptember 8——1 of 4
Fall breakOctober 15–162Monday, October 191 of 1
Thanksgiving breakNovember 261Friday, November 271 of 4
Winter breakDecember 23 to January 18Monday, January 41 of 4
Spring breakMarch 24–263Monday, March 291 of 4
Last day of schoolMay 26——1 of 3
Longest closure
Winter break, December 23 to January 1 (8 school days)
One-day closures
4
Closures starting Tuesday to Thursday
4
Staff days, no students
3: Jan 18, Feb 15, Apr 19
Early-release days
2: Nov 9, Mar 8
Most days off in one month
December, 7 school days
Months with no day off
September and May
Longest run of school days
28, October 19 to November 25

Every date

Every published date · Cook County ISD 166 · 2026–2027
DateWhat it isTime offDistrict’s own wording
August 31 to September 3Teacher work day, no students—No School - Teacher Professional Development Day
September 2Open House—Open House
September 7Labor Day—No School - Labor Day Holiday
September 8First day of school—First Day of School K-12
September 10First day for some grades—First Day of School Pre-K
October 6Testing—PSAT
October 15–16Fall break2 school daysNo School - Fall Break
October 17Testing—ACT
November 7Testing—SAT
November 9Early release—Early Release Day
November 26Thanksgiving break1 school dayNo School - Thanksgiving Break
December 23 to January 1Winter break8 school daysNo School - Winter Break
January 18Teacher work day, no students1 school dayNo School - Teacher Professional Development Day
February 15Teacher work day, no students1 school dayNo School - Teacher Professional Development Day
March 6Testing—SAT
March 8Early release—Early Release Day
March 24–26Spring break3 school daysNo School - Spring Break
April 10Testing—ACT
April 19Teacher work day, no students1 school dayNo School - Teacher Professional Development Day
May 22Graduation—Graduation
May 26Last day of school—Last Day of School
May 27Teacher work day, no students—Teacher Professional Development Day
June 12Testing—ACT

Sources

  1. District’s calendar: https://www.cookcountyschools.org/events (the source)
  2. District website: https://www.cookcountyschools.org
  3. Calendar feed read on October 8, 2026: https://thrillshare-cmsv2.services.thrillshare.com/api/v4/o/2847/cms/events

How these dates are read and labeled: Methodology.

Other Minnesota districts

Pipestone Area: 19 school days off Stephen-Argyle: 24 school days off Houston Public: 25 school days off