The movie Snow Day follows the story of Hal and Natalie Brandston, two siblings who are thrilled to find out that their school has closed for a snow day. They immediately set off to enjoy the day, but soon realize that it won't be as easy as they thought. They are faced with the challenge of avoiding the Snowplowman, a mean and grumpy man who plows the snow off the roads and is notorious for ruining everyone's fun on snow days.
As the day progresses, the siblings try their best to avoid the Snowplowman, all while embarking on exciting adventures with their friends. They build a snow fort, go sledding, and even create a fake school closure announcement in an attempt to extend their day off. However, their plans are constantly foiled by the Snowplowman, who seems to be determined to ruin their day.
Meanwhile, their parents are dealing with their own snow day struggles, including a broken furnace and a cancelled flight. The family's dynamics are explored as they all try to make the most of the unexpected day off.
In the end, the siblings come up with a plan to outsmart the Snowplowman and have the ultimate snow day. The movie ends with the family coming together, enjoying hot cocoa, and reflecting on the fun they had during their unexpected day off.