GREEN BAY, Wis. (WTAQ) - Summer ends Wednesday for hundreds of thousands of Wisconsin school students and their families.

It’s the first day of school for virtually all districts statewide. But classes have been delayed in at least 2 schools where mold turned up due to the hot and humid summer.

Tuesday, officials said the Kromrey Middle School in Middleton would not open until at least next Tuesday – and that will depend on the results of air samples in the building. Elevated levels of mold were found in two rooms at the school, and a marginally-high level was spotted in another room.

Also, the Gillett School District is closed until September 13th, after mold was found last month in an elementary school.

In Milwaukee, schools scrambled to make repairs following the heavy rains and floods in late July. Glendale Nicolet High School had $5 million in flood damage, and student registrations had to be delayed in mid-August.

In Madison, officials have tried to make safety improvements outside their schools to protect kids from heavy traffic. The Madison district has applied for a $300,000 grant to look for ways to encourage more students to walk and ride bicycles to school.