My state wants me to follow the public schools, but I do not.
I do not want late arrivals and that is their preferred option. Late opening.
I allow the parents to make the call. Late pick-up is $1 per minute, fiercely enforced, so I have no doubt they will make every effort to get here before the roads are impassable or simply stay home to not risk it.
I have taken kids home when unexpected weather hit (tornado/downed trees/powerlines/flash flood), though. If I did not know it was coming to give them notice, I don't hold them accountable for it, either. Fair is fair.