MINNEAPOLIS (WCCO) — There was a big change in humidity over the weekend. Saturday was sweaty, but by Sunday, the air was much easier to breathe. High humidity means there’s a lot of water in the air, but what causes it? Good Question.
“In meteorology, there’s this thing called the water cycle,” says WCCO Meteorologist Matt Brickman. “It rains, the water hits the ground, it gets hot, the moisture evaporates, it goes back up into the air and just keeps going around in that circle. That’s one way we can get moisture.”
He says another way for moisture to get into the air is through evapotranspiration, which is better known to some as “corn sweat.” That’s where the crops give off moisture and that moisture stays in the air to give it a second layer of humidity. This kind of humidity can blow into the Twin Cities metro area, but is more extreme in southwestern Minnesota.
Moisture can also move in with warmer winds because warmer air can hold more water. Sometimes that air comes through with a high pressure system, while other times it could just be a shift in the winds.
“So the Gulf of Mexico is pushing that moisture up through the southern states, up through the Central Plains and that eventually gets to us,” Brickman says.