LEWISTON — Snow days are piling up like snowbanks.

The frequent closing of schools for inclement weather — nine days so far this winter — means the last day of school for Lewiston students will be the first day of summer: June 21.

In Auburn, the last day of school will be June 20.

Both districts have used nine snow days this year, including Tuesday and Wednesday this week as a slow-moving nor’easter dropped 16 inches. Auburn has made up one day by giving up a teachers’ workshop day.

“Since I’ve been in Lewiston, this is the first time we’ve reached nine,” Superintendent Bill Webster said.

Most years, school calendars include five snow days, which is usually enough, said Auburn Superintendent Katy Grondin. This year, she included eight snow days in the calendar.

“Two years in a row, we’ve had a high number of snow days,” Grondin said.

There could be another big storm brewing for next week prompting snow day No. 10. WGME Weather Authority is warning that two models agree we could have another nor’easter Tuesday night into Wednesday.

In case there are more snow days, Webster said he’ll make a proposal to the Lewiston School Committee when it meets March 18 to ensure that the last day of school is no later than June 22, a Friday.

He doesn’t want school to linger into the last week of June.

“The custodians need people out of the building to do cleaning before summer school starts,” he said. And statewide, a number of professional development opportunities are happening that week, which teachers could not attend if there was school.

“Plus, I think going past that weekend I’d be concerned about attendance and people checking out,” Webster said. “Friday the 22nd is a drop-dead date, in my opinion.”

If there are more storm days, one way to avoid school in the summer would be to lengthen the school day. State regulations allow five hours of class time to qualify as one day of school, so if the school day were increased one hour during a week that would make up one snow day, Webster said.

His plan would have to be approved by the teachers’ union, the Lewiston School Committee and the Maine Department of Education commissioner.

“I’ll be asking them to approve the plan and give me the authority to move forward to ensure that school will not extend past June 22,” Webster said.

Auburn will also work on a Plan A if there’s one more snow day, and a Plan B in case there are two more storm days, Grondin said. She will meet with teachers’ union representatives Monday to talk about it.