The mercury will make a rare run for 100 degrees on Wednesday and Thursday in the Twin Cities, and Kahlen Rondot is excited.

"I get to see more people and I get to serve more ice cream," said Rondot, who was on the job Monday at Bebe Zito in Minneapolis, where customers were already lining up.

Others may not be as ecstatic as Rondot as the hottest weather of the year arrives in Minnesota for a weeklong stay — just as yet another bout of unhealthy air recedes. A chunk of heat that has been baking the southern and western U.S. for nearly a month will push into the state, and by midweek could have Twin Cities thermometers hitting the 100-degree mark for just the seventh time this century, the National Weather Service said.

The forecast calls for temperatures to reach or exceed 90 degrees for five straight days in the metro area — with the peak Wednesday and Thursday — before cooling down to the upper 80s Saturday, said Tyler Hasenstein, a meteorologist with the National Weather Service's Chanhassen office.

"We will definitely have a few days of excessive heat," he said. On the upside, "it won't be super humid. This is one case where the drought works in our favor."

Still, the heat and humidity can take its toll on anybody exerting themselves outdoors or living in places without air conditioning, said Dr. Tom Wyatt, a physician in the Hennepin County Medical Center Emergency Department. Heat-related illnesses — from dehydration to heatstroke — can strike quickly for people all ages.

"It's insidious," Wyatt said. "Stay hydrated. A lot of people won't drink unless they feel thirsty. By then it is too late."

Anybody experiencing confusion, dizziness, nausea, vomiting or loss of consciousness should call 911, Wyatt said.

Neither children nor pets should be left in cars. So far this year, 14 children younger than six have died of heatstroke in the U.S. after being left inside a vehicle, according to the website noheatstroke.org.

For a respite from the heat, Wyatt suggested visiting air-conditioned public places such as movie theaters, libraries, recreation centers and shopping malls. The Salvation Army has seven metro area service centers open for people who need a place to cool off, said spokesman Dan Furry.

The Anoka County Fair, which runs Tuesday through Sunday, is taking precautions to keep fairgoers and volunteers cool and hydrated, said fair manager Michaela Liebl. The fair brought in an air-conditioned trailer where workers can escape the heat, and set up large fans in animal barns to keep livestock from overheating. Guests can fill water bottles from jugs set up on the grounds, and cool off under water misters, she said.

"We have lots of shade and grass," Liebl said. "It's not all blacktop like at the State Fair."

July in the Twin Cities has been about 1.2 degrees cooler than average, but this week's blast furnace will likely change that, said Pete Boulay with the Minnesota Climatology Office. The Twin Cities' warmest temperature so far was 95 degrees on July 3.

Wednesday has the best chance of setting a new record high, Hasenstein said, with 99 degrees in 1999 the one to beat. Thursday's record is 100 degrees, set in 1955.

The mercury in the Twin Cities has reached triple digits just 32 times since 1873, including the most recent 101-degree reading on June 20, 2022. Temperatures have hit 97 degrees or higher only 72 times in the same period, the climatology office said.

"The forecast highest temperature of this week is consistent with heat we experience every two to five years historically," said State Climatologist Kenny Blumenfeld. "It's going to get hot, but not for weeks on end, and not at levels that rival our all-time records."