As temperatures rise, Hawaii schools consider "heat days" and teachers battle student fatigue

With only open windows and fans to cool the room down, students enter their non air conditioned classroom at Campbell High School, Monday, Aug. 3, 2015 in Ewa, Hawaii. Many public school classrooms across the Island are not equipped with AC, making it difficult for both teachers and students when the temperatures are high. In Hawaii, which has been experiencing record high temperatures, school officials are weighing whether it makes sense to have heat days, where they cancel school because it's simply too hot. (AP Photo/Marco Garcia) (The Associated Press)

With the gate propped half way open to provide ventilation, class is held in a converted garage at Campbell High School, Monday, Aug. 3, 2015 in Ewa, Hawaii. Many public school classrooms across the Island are not equipped with AC, making it difficult for both teachers and students when the temperatures are high. In Hawaii, which has been experiencing record high temperatures, school officials are weighing whether it makes sense to have heat days, where they cancel school because it's simply too hot. (AP Photo/Marco Garcia) (The Associated Press)

Mike Wooten, a teacher at James Campbell High School, lectures students in his non air conditioned classroom, Monday, Aug. 3, 2015, in Ewa, Hawaii. Many public school classrooms across the Island are not equipped with AC, making it difficult for both teachers and students when the temperatures are high. In Hawaii, which has been experiencing record high temperatures, school officials are weighing whether it makes sense to have heat days, where they cancel school because it's simply too hot. (AP Photo/Marco Garcia) (The Associated Press)

Teachers in Hawaii say their classrooms are so hot they are sending students to the nurse with symptoms of heat exhaustion.

Unbearably hot classrooms have prompted school officials to consider having "heat days" — like snow days — to cancel school when it's too hot to learn.

More than 90 percent of Hawaii's schools don't have air conditioning.

The lack of air conditioning comes during a particularly scorching year for the state. The National Weather Service says Honolulu temperatures reached record highs at least 25 times in the last year. And experts say Hawaii's cooling trade winds have been declining for decades.

The state Department of Education says it would cost $1.7 billion to install air conditioning in all Hawaii schools. A spokeswoman for the department says officials are open to considering heat days.