I probably wouldn't close for bad weather unless we were without heat in the winter or our house was flooding or it was otherwise dangerous for the kids to be here. Buuuuut, if parents were going to bring their kids to me in spite of dangerous road conditions - especially a SAHM!! - I probably wouldn't be inclined to be overly understanding if they were late picking up due to the weather. (Different if it turns bad midway through the day then if it's already blizzarding when you drop them off.) I wouldn't be getting up early so they could take extra time getting to work either!