The National Weather Service in St. Louis is predicting high temperatures Tuesday afternoon and into Wednesday.
The real temperature is predicted to be in the 90s, but the high humidity is expected to drive the heat index up to between 100 and 105 both Tuesday and Wednesday afternoons and into the evening. The highest temperatures will be between 1 and 7 p.m., according to the National Weather Service.
The elderly, chronically ill and very young should remain in air conditioning during the hottest part of the day and those who work outdoors are encouraged to take frequent breaks in the shade and drink plenty of water.
People are also reminded to check on family and friends who have health problems or lack air conditioning.
The heat is predicted to leave the region when a cold front pushes into the area Wednesday, bringing with it the possibility of severe thunderstorms, including large hail and damaging winds.
The United Way of Greater St. Louis has released the following list of cooling centers open in the metro-east during an excessive heat advisory or warning. An excessive heat advisory is issued when the heat index is expected to reach 105 degrees.
* Belleville Public Library, 121 E. Washington St., 9 a.m. to 8 p.m.
* Illinois State Division of Rehabilitation Services, 601 S. High St., 8:30 a.m. to 5 p.m.
* Belleville Public Library West Branch, 3414 W. Main St., noon to 8 p.m. Tuesday, 9 a.m. to 5 p.m. Wednesday.
* Salvation Army Belleville Corps Community Center, 20 Glory Place, 10 a.m. to noon and 1 p.m. to 2:30 p.m.
* Bethalto Public Library, 321 S. Prairie St., 9 a.m. to 8 p.m.
* Bethalto Village Hall, 213 N. Prairie St., 8 a.m. to 5 p.m.
* Breese Public Library, 530 N. Third St., 10 a.m. to 5 p.m.
* Cahokia Public Library, 140 Cahokia Park Drive, 9 a.m. to 7:30 p.m.
* Clinton County Health Department, 930-A Fairfax St., 8 a.m. to 4 p.m.
* Collinsville Public Library, 408 W. Main St., 9 a.m. to 8 p.m.
* Collinsville Township Senior Citizens Center, 420 E. Main St., 8 a.m. to 4 p.m.
* Edwardsville Public Library, 112 S. Kansas, 9 a.m. to 9 p.m.
* Granite City Township, 2060 A. Delmar Ave., 8:30 a.m. to 4:30 p.m.
* Illinois Department of Human Services Madison County Office, 1925 Madison Ave., 8:30 a.m. to 5:30 p.m.
* Salvation Army of Southwest Madison County, 3007 East 23rd St., 9 a.m. to noon and 1 to 4 p.m.
* Glen Carbon Senior Center, 157 N. Main St., 8 a.m. to 7 p.m.
* Glen Carbon Centennial Library, 198 S. Main St., 9 a.m. to 8 p.m.
* Faith Countryside Homes, 1331 26th St., 8 a.m. to 4 p.m.
* Weinheimer Community Center, 1100 Main St., 8 a.m. to 5 p.m.
* Lebanon Public Library, 314 W. St. Louis St., 10 a.m. to 7 p.m.
St. Paul's United Church of Christ, 123 E. Dee St., noon to 6 p.m.
* Leu Civic Center Inc., 213 N. Market, 9 a.m. to 8 p.m.
* O'Fallon Public Library, 120 Civic Plaza, 9 a.m. to 8 p.m.
* Monroe County Health Department, 901 Illinois Ave, 8 a.m. to 4:30 p.m.
*Wood River Fire Station, 501 E. Edwardsville Road, 259-0984. Call for hours.
* Wood River Public Library, 326 E. Ferguson Ave., 9:30 a.m. to 8 p.m.
* Wood River Roundhouse Parks and Recreation, 633 N. Wood River Ave., 8 a.m. to noon and 1 to 5 p.m.
East St. Louis
* Fairmont City Library, 2870 N. 44th St., noon to 8 p.m.
* Illinois State Department of Human Services St. Clair County Office, 225 N. Ninth St., 8:30 a.m. to 5 p.m.
* Clyde C. Jordan Senior Citizens Center, 6755 State St., 8 a.m. to 4 p.m.
* East St. Louis Public Library, 5300 State St., 9 a.m. to 8 p.m.
* Continuum of Life, 1274 N. 37th St., 8:30 a.m. to 5 p.m.
* Holy Angel Catholic Urban Programs, 1410 N. 37th St., 8 a.m. to 8 p.m.
* Washington Park City Hall, 5218 N. Park Drive, 9 a.m. to 5 p.m.
* Lessie Bates Davis Neighborhood House, 1200 N. 13th St., 8:30 a.m. to 5 p.m.
* Salvation Army East St. Louis Corps Community Center, 616 N. 16th St., 9 a.m. to 4 p.m.
* Caseyville Township Office of General Assistance, 10001 Bunkum Road, 8 a.m. to 5 p.m.
* Fairview Heights Public Library, 10017 Bunkum Road, 10 a.m. to 8 p.m.