FALCON HEIGHTS — Minnesota State Fair officials and fairgoers braced on a steamy Sunday for what could be the hottest stretch of weather at the event in 65 years.

An excessive heat warning took effect Sunday and runs through Tuesday for a large part of southern Minnesota and surrounding states, while a heat advisory covers the rest of the southern two-thirds of the state. Highs have been forecast to hit the 90s, with heat indexes to reach 100 to 110. Nighttime conditions aren’t expected to cool below the 70s to lower 80s.

Fair officials said they were working closely with emergency services at Regions Hospital and the St. Paul Fire Department to ensure that guests who need medical attention get it promptly. They said 51 people were treated for heat-related issues Saturday, including 10 who had to go to the hospital.

The National Weather Service said the temperature on the fairgrounds was 96 at 4 p.m. Sunday.

Misters were set up at two medical aid stations on the fairgrounds to cool off guests. Several businesses and booths also have misting fans.

Marching band directors were told that their musicians must bring cooler clothing instead of their regular uniforms.