KSDK - Any school leader will tell you that cancelling school is not a decision they take lightly. With the low temperatures Friday and early next week, districts will have to consider a call they haven't had to think about for years.

We talked to two districts on Thursday that say wind chill is a factor in determining whether school will be called off since so many kids have to stand at their bus stops for extended periods of time.

Edwardsville is one of the dozens of school districts in the bi-state that cancelled class Thursday because of the overnight snow.

Superintendent Dr. Ed Hightower says whenever there's weather like this they send about a half dozen buses out to check the more rural routes. A decision is made to cancel by 4:30 and then he calls parents.

Heading into next week, wind chill will be a huge factor in whether the district's 7,500 students go to school Monday.

"...when you cover the amount of radius that we cover, then you have to keep in mind that those little kids, small kids may be standing out there for a long period of time. You cannot expose the children to those types of conditions," Hightower said. "So looking at what we have coming up on Monday, we will study this very closely over the weekend and if we get what we think we're going to get, the coldest temperatures since 1999, there's a good chase we will err on the side of caution and possibly cancel school for Monday. But time will tell."

We also spoke with the Fort Zumwalt superintendent. He says if we're just looking at wind-chill by itself, it needs to be 20 to 30 below zero for them to cancel school. If it's wind-chill combined with other weather conditions, it would need to be about 10-below to cancel.