Minnesota town hit one of the highest dew points on record, 120-degree heat index

Location: Preston.

Heat index: 120 degrees.

The small town in southeastern Minnesota is home to just over 1,300 sweaty residents who, perhaps not to their knowledge, experienced a near record when the dew point surged to 86 degrees multiple times on Monday.

That's just shy of the all-time state record 88-degree dew point set in Moorhead on July 19, 2011. The air temperature in Preston at 12:15 p.m. was 88 degrees, which when combined with the 86-degree dew point created a heat index of 116 degrees.

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That lasted for about 30 minutes before the dew point dipped to 84, only to rise again to 86 to go along with a 90-degree air temperature and 120-degree heat index at 1:15 p.m.

The maximum heat index in recorded Minnesota history belongs to Moorhead at 130 degrees on that historic date in July 2011.

Bring Me The News meteorologist Sven Sundgaard explains that moisture is pooling in southern Minnesota as winds at the surface converge, luring in an air mass from the Gulf of Mexico. The air has to pass through the Iowa and Minnesota cornfields, which are also critical because corn stalks sweat, leading to more moisture and higher dew points.

Related: Extreme heat indices, significant severe storms in Minnesota

The record dew point in the Twin Cities is 82 degrees, which was also record on July 19, 2011. That record probably won't be tied or broken at MSP Airport (the official recording station for Twin Cities weather data), but Blaine got close at 9:45 a.m. with a dew point temperature of 81 degrees.

At 1:20 p.m. Monday, the temperature and dew point at MSP Airport was 90 and 76, respectively. That makes for a heat index of 101 degrees.

Heat is no laughing matter. In fact, 682 Minnesotans wound up in emergency rooms due to heat-related illness in 2023 and two of those patients died, according to the Minnesota Department of Health.

"Any person exposed long enough to excessively hot temperatures is at risk of developing a heat-related illness. Older adults, infants and children, people with chronic conditions, and outdoor workers are more vulnerable to the heat," the health department says.

The Twin Cities and all of southeastern Minnesota is under an excessive heat warning until 8 p.m. Monday.