MADISON, Wis. -- Kromrey Middle School in Middleton remains closed due to mold problems at the school, and other schools in the area have come close to shutting down because of it.

For this week's "Good Question," WISC-TV looked into why there seem to be more cases of mold.

Experts said this summer's weather has been the perfect storm for mold growth.

Martine Davis from Indoor Environmental Testing said it has been a busy summer for mold problems.

"I think what we're seeing this summer particularly is more what we call in the field surface mold," Davis said. "As opposed to mold that's in a wall cavity as a result of a leak."

Davis said the wet and humid summer weather is to blame for the mold problems. Mold can typically grow when the relative humidity is above 60 percent. And it becomes even more of an issue when there's no air circulation, which is pretty common in a school over the summer months.

"This year, I'm attributing it to the high humidity we've had. We've had many days in a row with very high relative humidity," Davis said. "A lot of people are not using air conditioning or fans."

Madison College building expert John Stephany said another big problem is that buildings used to breathe -- and naturally circulate air. That doesn't happen anymore, as most structures are sealed up for maximum energy efficiency.

He said that means minimal air movement -- with the right weather -- translates to mold spores gathering and growing.

"You're never going to stop mold -- it's always there," Stephany said. "It's in the air we breathe. It's always been there and always will be. But you want to keep the levels of the bad stuff down."

The kind of mold that's mostly being found right now is surface mold. Experts said it's problematic but much easier to deal with, compared to the problems that Madison's Chavez Elementary School saw in 2002 when a leak during construction caused mold growth in the walls.

For surface mold, soap and water will usually do the trick -- along with dehumidifying the structure and keeping water out, WISC-TV reported.