The National Weather Service in North Little Rock on Sunday issued a heat advisory for parts of east and central Arkansas.
The advisory will remain in effect until 7 p.m. Monday, the agency said.
Temperatures in Little Rock on Sunday are forecast to reach 98 degrees, the agency said, and the heat index is expected to rise as high as 105 degrees.
On Monday, forecasters expect a high of 99 degrees with a heat index of 109 degrees.
The combination of high temperatures and high humidity increases the risk for heat-related illnesses. The agency advises people dealing with hot conditions to stay in air-conditioned areas and out of the sun as much as possible, keep hydrated and check on relatives and neighbors.