PHILADELPHIA (CBS) — Snow days are taking a toll on school calendars this winter, but school districts have been able to get those make-up days in, including sacrificing this year’s spring break.

John Callahan of the Pennsylvania School Boards Association says most districts set their calendars well in advance of the start of a school year and do account for a certain number of snow days.

School Closings

“There’s probably three to five of them built into the calendar,” Callahan tell KYW Newsradio. “So, we’re prepared for kind of the winter mess that happens in Pennsylvania. But, of course, when you get beyond that, things become a bit more challenging.”

Callahan says this winter has been especially rough and more snow days meant subtracting days from the spring break and from days built in toward the end of the school year.

See Full List Of Community Cancellations

He says he knows of no districts planning to tack on days to the end of the year, something they prefer not to do because of graduation.

Pennsylvania requires 180 days of instruction and there are provisions for waivers under extraordinary circumstances, something Callahan says he doesn’t see happening for any district this year.