Cambridge Public Schools closed campuses – such as at the Graham & Parks School on Linnaean Street – March 13 in favor of remote learning to prevent spread of the coronavirus. (Photo: Marc Levy)

Guidelines from the state Department of Elementary and Secondary Education on how to calculate the last day of school could cost the district an additional $2 million to stay open for four additional days this year.

It comes down to what counts as a school day. In a year with no snow days, the last day of school would be June 16. This year the last day would be June 17 to make up for the year’s single snow day, complying with the state-mandated total of 180 days of classes in a school year.

In a quirk of accounting, the state counts snow days as school days even though a school is closed – so this year June 17 is called the 181st day even though students will have attended 180 of them.

Yet the district’s 2019-2020 calendar, updated March 23, with an email sent to parents March 30, says June 23 is the last day of school. This adds an additional four days to the school year for a total of 185, per the state’s accounting method.

It appears the district updated its calendar during the initial flurry of campus coronavirus closings in response to state guidelines from late March – which said school districts must use their five annually allotted snow days to make up for school days lost between when campuses closed and remote learning began.

But this should not apply to Cambridge, superintendent Kenneth Salim said, because schools closed Friday, March 13, and remote learning began Monday, March 16, with no loss of school days.

How to account for April vacation adds another twist. An April 3 memo from DESE commissioner Jeffrey Riley says any district that kept schools open during the four non-holiday days of April vacation (April 20 is Patriots’ Day, a state holiday, and does not count as a vacation day) is not required to “go beyond its scheduled 181st day.”

The memo also says a district that kept its April vacation was expected to resume its remote learning program April 27 and conclude the school year “no earlier than the previously scheduled 185th day.”

Cambridge did close schools during its April vacation, and under this rule it is required to keep schools open an additional four days, until June 23.

If required by the state, each additional day is projected to cost the district $500,000, for a total of $2 million, because it can be argued that teachers will have worked for 184 days during the year, Salim said. It would also require the district and the Cambridge Education Association to negotiate a change to their collective bargaining agreement.

Mayor Sumbul Siddiqui and Salim, during the School Committee meeting held Thursday, said an appeal from the committee will be sent next week to change of the last day of school to June 17, noting that no school days were lost during the transition. The mayor and the committee are reviewing the draft letter, which will be discussed at the next meeting before submission, Siddiqui said.

It is uncertain how the state will reconcile what appear to be conflicting guidelines.

Attempts to reach the associate commissioner at DESE for clarification were unsuccessful.