Ten classrooms at Myers Middle School either had no or reduced air-conditioning recently.
Problems in four classrooms had been fixed by Wednesday afternoon, said Julie Zwahr, spokeswoman for the district.
"We are continuing to work through the remaining six classrooms and hope they will be fixed soon," Zwahr said via email Wednesday.
It is not clear how long the classrooms had been without air-conditioning.
Zwahr said students and staff are always allowed to bring extra water during "extremely high-heat days," and that classes were moving into unaffected areas on a class-by-class basis.
She said the district is bringing in additional, temporary technicians to fix the remaining problems.