Leesville Road and Millbrook high schools were the first to take their turn in North Carolina State University's Reynolds Coliseum, which lacks air conditioning.
Audience members estimated the temperature inside the building was between 85 and 90 degrees on Wednesday evening.
"With this thing on, the heat doesn't get out," graduate Joshua English said, pointing to his gown. "I was basically boiling."
"We did have some family members that weren't able to make it because of the heat," his mother, Lisa, said.
The school system must use Reynolds, because it is the only facility in the area that can hold enough people and guarantee dates far enough in advance, said Greg Thomas, a spokesman for the Wake County Public School System.
Thomas said scheduling rules out using the RBC Center. Planning for graduations begins up to a year before, and the RBC managers can't commit to date that early, due to potential conflicts with events such as hockey playoffs, Thomas said.
Organizers said they have plans in place to make the graduations as comfortable as possible.
- Water will be available for sale inside.
- Cooling stations will be set up at the north entrance.
- Grads, families and friends are encouraged to dress for cool comfort.
- Extra fans will be deployed throughout the venue.
Principals pledged to try to keep the ceremonies to under an hour and 15 minutes.
Other schools have the benefit of a cooler environment. Fuquay-Varina, Athens Drive, Knightdale and East Wake high schools will hold their ceremonies in Raleigh's air-conditioned Memorial Auditorium.
Thomas said the problem of holding graduation ceremonies in un-air-conditioned venues will be relieved after the new Raleigh Convention Center opens this September.
"Next year, when the civic center is reopened, we shouldn't be facing these issues," Thomas said.
Parents of some graduates said they would just try to deal with the uncomfortable temperatures as best as possible.
"It's kind of hard, but when you are thinking about what you are there for, you kind of ignore that," Jackie McCummings, the mother of a graduate, said.