Nearly every superintendent in Butler County has decided that today's expected wind chill factor of minus-20 is an unsafe temperature for students and staff.

Many have delayed the start of the school day, since students returned to class after the Christmas break, as temperatures have stubbornly remained in the single digits or teens.

Brian White, Butler School District superintendent, said he considers the demographics of his far-flung district when making a decision on whether to delay or cancel school.

He said even a slight delay in a bus arriving at a stop during sub-zero temperatures could result in skin damage from frostbite.

“And we have a large number of walkers, some from the city, who walk up the hill to the senior high,” White said. “That's a long walk on a cold day.”

White has also witnessed students who wear shorts no matter the weather.

“Kids don't make that good of decisions for dressing in the cold,” he said.

Frank Prazenica, South Butler's acting superintendent, said he has one main consideration when deciding whether to delay classes or close schools in a snow or extreme-cold event.

“Always, the most important factor is the safety of the children and employees and everyone involved with the schools,” Prazenica said.

He said on days like Thursday, when wind chill factors dipped below zero but classes were not delayed or canceled, his concern is the district's facilities and the heat and water systems in each building.

Prazenica said a pipe froze recently during the ongoing cold snap and began leaking, so he made the decision to delay after-school activities for two hours while the maintenance staff fixed the pipe.

“We were back in progress for evening activities,” he said. “We have quality people on our staff who can make those repairs.”

His long tenure in leading school districts has rendered Prazenica pragmatic regarding the unpredictable northern winters.

“You just have to deal with the weather,” he said. “You make the best possible decision for all of your school community.”

Sean Arney, superintendent at Moniteau School District, said the recent freezing conditions have kept him and his peers hopping.

“This week has been really unique in that there were a lot of early mornings with severe negative temperatures,” Arney said.

He said it is easier to make a decision in a snow event than in predicted cold temperatures because snow can be measured but cold temperatures can fluxuate minute to minute.

“There's no specific degrees, but when we're in the negatives we're cautious about kids walking to school or standing at bus stops for long periods of time,” Arney said.

Arney said he never cancels school for the next day while the current day is ongoing because it confuses and sometimes alarms parents when they get a message from the school while it is in session.

Arney said when the temperature falls this low, there is no sense in delaying classes for two hours.

“The air temperature in the early morning is consistent with the entire day in negative degrees with the wind chill and is not getting out of single digits, and we feel it's not a safe environment for the kids,” he said.

Arney is new to Western Pennsylvania, having come to Moniteau from the Philadelphia area.

“We would never close for temperatures (in his previous district) because we never got down this low,” Arney said. “This is the coldest air temperature with the wind chill I've seen.”

Seneca Valley and Mars school districts are also careful to make decisions on delaying or canceling school in snow or cold temperatures.

“Calling a snow or extreme temperature delay or closure is certainly not an easy decision to make, and it's one that is done with careful consideration and input,” said Linda Andreassi, communications director for the Seneca Valley School District.

More often than not, administrators are reviewing data the night prior, getting a general outlook for the following day. According to Wes Shipley, Mars School District superintendent, that homework includes speaking with superintendents from other school districts to determine their often-changing plans.

The real work begins at about 4 a.m., when the districts send crews out to monitor the roads. They also listen to reports from municipal workers, who are typically working at that hour to clear the roads before the morning commute.

“We monitor many data points,” Andreassi said. “The type of storm ... type of accumulation ... predicted accumulation, temperature, wind chill, wind speed and duration of the storm. We consult with the National Oceanic and Atmospheric Association, especially their hour-by-hour predictions, our buildings and grounds department, local authorities, our transportation company and neighboring school district superintendents.”

For days with low temperatures but no accumulation, Shipley said he monitors true air temperature and wind chill. Both he and Andreassi said a baseline of -10 degrees exists for monitoring the temperature, and officials also pay attention to weather alerts and advisories.

“A weather alert takes precedence,” Shipley said. “I'm also looking to see if there is a warming effect as opposed to is there not. A delay for cold allows for looking at the prospect of it warming up enough later once the sun is up.”

That warming effect — or lack thereof — can make the difference between a delay or cancellation, Shipley said. A decision for delay is typically made by 5:15 a.m., with a cancellation decision made by 7:15 a.m. Shipley and Andreassi both said cold weather delays and cancellations are always made with the safety of students in mind.

“As the chief educator of the district, I try to decide if we can have school in a safe way,” he said.

However, that judgment call doesn't override decisions made by parents who may feel it to be too cold for their children to make the trek to class.

“I think it's also important to remind parents that they always have the option of keeping their child home if they feel the weather or weather conditions are unsafe,” Andreassi said.

Shipley agreed.

“Parents have the right to disagree with me and keep their children home,” he said, adding the day would be marked as an excused absence for students who don't generally have attendance issues.

Though a decision is made by early morning, Shipley said the communication doesn't stop there. He said he remains in contact with superintendents from neighboring districts, who may have come to a different conclusion despite similar conditions.

“I let them know that maybe I had to cancel because a salt truck broke down and a road isn't clear,” he said, adding that information is useful for answering questions from district residents and allows for consistency in future decision making.

J.W. Johnson Jr., the Eagle's Cranberry Township bureau chief, contributed to this report.