UPDATED: 1:53 p.m.
Teachers have been required to conduct remote instruction since schools shuttered in mid-March.
Private schools with later academic years are closed until at least June 30, Murphy said.
Murphy said he waited as long as possible to make a final decision.
“We did want to give this every shot we could — in particular, for the seniors,” he said, “and it just feels like a bridge too far.”
The state will be meeting with parents and other stakeholders to consider summer courses, as well as to discuss the 2020-2021 school year, he added.
“There's a lot to consider about how the school year may differ once our students and faculty return,” he said during Monday's news conference.
The state is seeking $310 million in federal assistance, Murphy announced. At least $280 million would go to schools to cover the cost of buying educational technology, cleaning buildings and getting support services for students.
The department will also work with school officials to share ideas on how to safely recognize 2020 high school grads.