Our days are added on at the end. I hate it! We currently have a superintendent who loves snow days. Last week, he cancelled school for Wednesday on Tuesday afternoon before one snowflake had even fallen! (And as a side note, there wasn't anywhere's near as much snow as was predicted and the kids definitely could have gone--like almost every other community in the area) As of now, we aren't getting out until June 23.
For the OP, if we don't go sledding, we usually have a jammy day on snow days!