Excessive heat affecting some central Iowa schools. How to stay safe and cool:

A heat advisory has been issued, resulting in a handful of early dismissals for the first Monday back for students in central Iowa schools.

Temperatures will reach as high as 99 degrees with a heat index of 110 degrees in Des Moines, according to the National Weather Service. The heat will gradually decline as the week goes on; thunderstorms also are possible.

Where will it be the hottest in Iowa on Monday?

What schools have early dismissals on Monday?

• Dowling Catholic : Dismissed at 10:30 a.m. due to the air conditioning system failing.
• East Marshall Community Schools : Two-hour early dismissal on Monday.
• Gladbrook - Rienbeck : Dismissed two hours early.
• Des Moines Horizon Science Academy : Closing at 12:30 p.m.
• Interstate 25 Community School District : Noon dismissal time Monday.
• Southeast Warren : Closing at 1 p.m.

Business as usual for DMPS

Monday is the first day of school for Des Moines Public Schools, and business will continue as usual with no changes to the schedule. District officials will continue to monitor the weather if changes need to be made to the first day of school.

Most school buses in the Des Moines school district do not have air conditioning. Bus drivers will take steps to make buses as comfortable as possible by opening all windows and vents and turning on fans. A heat index at or exceeding 100 degrees will move outdoor recess, events and activities indoors.

All classrooms in the district are air-conditioned. Each school building also has hydration stations.

Polk County activates extreme temperature plan

Polk County activated its extreme temperature plan in response to the heat Sunday. The plan is initiated when the temperature is 95 degrees or above, and for two consecutive days when the heat index does not drop below 75 degrees at night, according to the Polk County website . There will be emergency shelters available for those in need of amnesty. Central Iowa Shelter Services will take any age during day services and those 18 and older for overnight services.

The Des Moines Area Regional Transit Authority (DART) will offer free rides to cooling centers. It is advised to call ahead to ensure there are openings before visiting a cooling center.

Where are cooling centers in the Des Moines metro?

Avoiding the heat is the most effective way to stay safe and cool during extreme heat. The Polk County extreme temperature plan allows for dozens of buildings, including libraries, city halls and community centers, to be used for cooling centers for anyone to use.

DART provides free rides to cooling centers . When you board, tell the driver you need to go to a cooling center.

Cooling centers in the Des Moines metro include:

• Des Moines Central Community Center, 2008 Forest Ave.
• Des Moines Central Library, 1000 Grand Ave.
• Des Moines Forest Avenue Library, 1326 Forest Ave.
• Des Moines Four Mile Community Recreation Center, 3711 Easton Boulevard
• Des Moines Northwest Community Center, 5110 Franklin Ave.
• Polk County Health Department, 1907 Carpenter Ave.
• Des Moines South Side Library, 1111 Porter Ave.

A full list of available cooling centers can be found on the Polk County website .

Kate Kealey is a general assignment reporter for the Des Moines Register. Reach her at kkealey@registermedia.com or follow her on Twitter at @Kkealey17 .

Reporting contributed by Kyle Werner.

This article originally appeared on Des Moines Register: Excessive heat affecting some central Iowa schools. How to stay safe and cool: