When should school be cancelled?

I'm no cold weather expert, but the reasons to close school should be about safety. Yes, I did go to school in sub-40, uphill both ways when dinosaurs ruled the Earth. That said, there are families that don't have adequate winter clothing for their children. The risk of a kid getting severe frostbite or worse is reason enough to keep the kids at home. It would be better if ISD #709 had a fixed policy on the matter. When you have a policy, everyone can follow it and parents can look it up. A lack of policy leads to inconsistent decisions and confusion.

During this last cold snap the current policy for Duluth schools was schools were open but if you chose not to send your children they were excused from absence.  Also the bus companies have a say in the matter if they deem conditions too hazardous for driving.

I think the reason to avoid a policy is that what the weather is like at the moment is often less important than what the weather will be like hours into the future.  You don't want to arbitrarily announce school is on because it's three degrees warmer than a set threshold while knowing that the forecast indicates it will be colder later in the day. The policy ends up being meaningless if you have to break from it all the time, so there is little sense in having a policy. Weather is pretty unpredictable. It's always a judgement call in the end, so we might as well call it that from the beginning.

Judgement calls are meaningless in an age of internet comments and talk radio making absolutely sure that the judgement of any particular governing body is suspect.

There is also an element of liability for the school district that goes into these decisions. In today's litigious society consideration must be given not only to safety but to the likelihood of a lawsuit being filed because a kid got frostbite, etc.