New York City public schools were open Monday, but a quarter of students didn't go, according data from the Department of Education tracked by WNYC's Data News team. On a normal day, school attendance is about 90 percent across the city, but Monday it was just below 75 percent.

Mayor Bill de Blasio announced Sunday that he would keep schools open, and that he'd change his mind if the forecast worsened. Early Monday morning, he confirmed his initial decision.

During a snowstorm a year ago, the mayor and schools chancellor Carmen Farina were criticized for making the decision to close schools at around 5 in the morning.