Record-high heat set Twin Cities pavements sizzling Sunday, as a hot, humid weather system settled over Minnesota for a weeklong siege.

The National Weather Service issued an excessive heat warning for much of the state through Tuesday night, but the first cooler air isn’t expected until Thursday.

Sunday’s high of 96 degrees in the Twin Cities broke the 94-degree record set in 1948, taking a toll on visitors to the Minnesota State Fair, where several people were treated for apparent heat exhaustion, officials said.

Another record of 96 or above is expected Monday, although there was a 30 percent chance of rain early in the day.

Minneapolis schools have canceled all outdoor after-school athletics practices for Monday, when classes open. The district already has started to cool buildings, although 18 of its 54 buildings lack air conditioning. Schools also will provide extra water and advised students to wear light, loose clothing of light colors.

In Fargo, officials canceled classes at the five elementary schools in the district that don’t have air conditioning. A cool front from Canada should drop temperatures into the upper 80s Thursday, but until then daytime temperatures will remain above 90 degrees, said meteorologist Bill Borghoff at the National Weather Service office in Chanhassen. High in the 90s likely will return for the Labor Day weekend, he added.

Borghoff suggested that people working outside drink plenty of water and take frequent breaks. For fairgoers, he said cold water is a much better way to cool down than drinking pop or beer, which can dehydrate a person.

Some fairgoers were taking Borghoff’s advice Sunday, when beer sales seemed lower than on Saturday, said vendors at the Minnesota Craft Brewers Guild exhibit. All seven cashiers at the Midwest Dairy Association milk counter were busy Sunday afternoon, selling more than 2,400 chocolate malts by 2:30 p.m. But fewer people seemed to take free refills on their $1 milk cups, said foreman Terry Simon. “People are saying milk is heavier. They’d have a cup then go find some water.”

Simon also said it seemed the heat had reduced attendance and potential milk drinkers, leading him to expect that he would sell less than the usual daily average of 29,000 gallons of white and chocolate milk.

A lot of people were using stick fans Sunday outside the butter carving booth in the warm Dairy Building, said Princess Kay of the Milky Way finalist Erin Orth. Orth, 18, of Winona, sat in the booth, where the temperature is kept at 40 degrees, while a sculptor carved her likeness out of a big block of butter.

After riding on the Princess Kay float in the hourlong parade Sunday, Orth returned to the carving booth, but said she was so warm she didn’t need the winter coat and snow pants she usually wore.

Respite from the heat

“It’s a great day to be in the butter booth,” she said.

In addition to drinking water and savoring cold treats and beverages, fairgoers found other ways to keep cool. Some ate at tables around the outside of O’Gara’s bar-restaurant where a mister sprayed coolness from the water gutters.

Kevin and Leaza King of Elk River took turns wearing a water-soaked shammy-like cloth around their necks. Their two kids preferred Nitro ice cream sold in the Food Building.

“It’s really creamy and mega-frozen,” said Elisabeth King, 15. “We get it every year. We wouldn’t leave the fair until we have it.”