PITTSBURGH (KDKA) — The warmer weather means kids are back in class after spending much of last week learning from home because of the cold. But districts are burning through their so-called flexible instruction days. That means traditional snow days may be back on the books, but it could keep kids in school a little longer this spring. During a stretch of below-freezing temperatures, almost every school in the Pittsburgh area was empty. But what’s the difference between a snow day and a remote learning day? According to Pennsylvania state guidelines, during an old-fashioned snow day, the school is…..