High temperatures coupled with uncomfortable humidity levels could push the heat index close to 100 Tuesday, forecasters said.
The forecast prompted Bishop Noll Institute in Hammond to announce an early dismissal, with the school day ending one hour early at 2 p.m.
No official heat warnings or advisories were issued by the National Weather Service.
The region is expected to get a short break from the 90-degree heat Wednesday after a weak cold front brings showers and possible thunderstorms early Wednesday morning. High temperatures on Wednesday are expected to in the mid-80s.
Thursday through Saturday, highs will be back in the 90s.
The coolest day in the forecast is Labor Day, with a high of 80.