FARMINGTON – On Wednesday, it was too hot to stay indoors and too hot to go outside.

That’s what teachers in several Franklin County schools were facing when the temperature topped 90 degrees.

Making the situation more challenging was that Wednesday was also the first day back of school for several districts.

At the Mallett Elementary School in Farmington, where school started Tuesday, the second floor rooms registered above 90 degrees on a thermometer before the school day even started, officials said.

All the superintendents contacted Wednesday had visited their schools during the day to gauge how the heat was affecting the learning environment and to make sure there were enough fans to go around.

The conditions were difficult but not impossible to handle, they said, and there were no plans to cancel classes Thursday.

The heat wave is expected to last into Friday, according to the National Weather Service, which has issued a heat advisory for Maine.

At Franklin Memorial Hospital in Farmington, several patients had come into the emergency room suffering from effects of the heat and had to be given fluids, but medical personnel reported that was to be expected, according to a hospital spokesperson.

“Teachers are keeping the windows open, fans going, and parents are being told that children should be dressed for the hot weather and should bring liquids. They have access to water at any time they want it,” said Michael Cormier, superintendent of Mt. Blue Regional School District in Farmington.

“I think we are in pretty good shape but the construction projects make it a bit confounding,” he said.

Two school building projects — Mallett School on Middle Street and Mt. Blue High School on Whittier Road – are under way. Contractors are putting water down to minimize the dust, he said.

“This is really hot for us. We are not acclimated to this kind of heat,” he said.

Mallett, which was built in 1931, and the 40-year-old high school have no insulation. They get hot quickly in the summer and are hard to heat in the winter, he said. That will change with the new buildings, which will both be energy-efficient.

“On the third floor of the high school, it is always hot,” Cormier said. “We usually get this kind of weather in June and faculty has found ways to deal with it.”

“The teachers are very attuned to the children in their classrooms. In some cases, they have relocated their class to other parts of the school that were cooler, and at the high school, one teacher I saw had taken the class out onto the front lawn,” he said.

Classes at Mt. Blue started Wednesday.

Susan Pratt, superintendent of the Livermore Falls school district, said teachers were keeping kids indoors on this first day of school because it was cooler there than outside.

“The warmest building is the high school. It is a two-story structure and the second story is the worst. We had a lot of fans going,” she said.

“It is not comfortable but it is tolerable,” she said. “This is one of the warmest days in September for school that I remember. I think this must be a record.”

In Jay, Superintendent Robert Wall said staff were doing all they could to beat the heat and he had not received any calls from parents concerned about the conditions.

“We are recognizing the heat and are making sure we have plenty of hydration available. I spoke to the staff and overall, they said we had a very good day,” he said.

The weather service advisory reported that the high heat accompanied by the high humidity caused the heat index values to rise to near 100 degrees Wednesday. Conditions will continue to be “uncomfortable and potentially dangerous, especially in hot buildings without air conditioners or proper ventilation,” according to the advisory.

Heat illnesses are possible and people are being encouraged to drink plenty of fluids, stay in an air-conditioned room and out of the sun, the alert stated.