The school system has joined the growing number of cities and counties opting to dismiss classes early due to extreme heat. Some schools will begin dismissing students at 11:00 a.m. No school will be open for more than four hours.

All after-school activities have also been canceled.

The move comes as temperatures are expected to be in the 90s Tuesday. As of 2021, just 17% of school buildings in the Milwaukee Public School system were equipped with air conditioning.

The school system said the closures were being made “for the safety of students and staff during extremely hot weather.” No decision has yet been announced about classes on Wednesday, but temperatures are expected to be lower, with a marked drop by Thursday with highs in the 60s.

Milwaukee’s decision follows several other districts around the country, which are trying to cope with this summer’s record-high temperatures. It has been a growing problem for several years, reaching back to well before the pandemic.

Kansas City Public Schools released students early for the better part of a week in late August, as many schools and school busses there do not have air conditioning.

While parents are understanding of the move, it has upset some guardians, who have to quickly arrange for childcare or adjust their working hours with little notice.

That’s the same worry parents in roughly 850 school districts are facing in cities and municipalities that have shifted from a five-day school week to a four-day one this year. Officials in those districts say the move is meant to incentivize teachers to remain on the job and recruit new ones.