HONOLULU (AP) — In her 90-degree classroom, Hawaii teacher Sharon Nichols is so desperate to keep her third-graders cool that she walks around the classroom spritzing them with ice water.

Like virtually all schools in the normally temperate state, her building lacks air conditioning, and that's been fine in the past. But Nichols and other Hawaii teachers say it's been so hot this year that students have showed symptoms of heat exhaustion and had to go to the school nurse.

"I just worry about the kids that start looking sickly and tired in my class," Nichols said. "It's very hard to focus. I'm up here teaching, and I'm telling the kids 'Come on, wake up,' and I'm falling asleep myself."

The Hawaii teachers union says if it's too hot to pay attention, it's too hot to go to school. Its president is calling on the state to establish "heat days" — like snow days — and cancel school when it's too stifling to learn.