A sudden drop in temperatures is forecast in four central U.S. states, prompting meteorologists to issue a series of freeze warnings on Monday.

National Weather Service (NWS) meteorologists issued freeze warnings for seven states on Monday, with some of those states expecting temperatures to reach around 30 degrees in a few hours overnight.

Missouri, Nebraska, Kansas and South Dakota are the states expecting the biggest drop in temperatures. During the day Monday, temperatures were in the upper 50s and low 60s for each of these areas, with forecasts calling for temperatures to drop as much as 20 degrees overnight. Most frost warnings are expected to come into effect overnight.

NWS meteorologist Michael Connelly said News week that it’s “very common” in the Aberdeen, South Dakota area to see temperatures drop this low this time of year.

“We are very close to what would be the normal end of the agricultural season,” he said.

On Wednesday, temperatures are expected to rise slightly in some of the affected areas.

“Fall is a season of ups and downs! Expect another hard freeze tonight, with a cool start to the week before temperatures return to above normal,” the NWS office posted in Aberdeen, South Dakota, on X, formerly Twitter. “With strong southerly winds, these warmer temperatures come with increased fire risk.”

Minnesota, North Dakota and Michigan also had frost warnings in place. Temperatures are expected to drop 20 to 25 degrees overnight.

“Freezing and freezing conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing,” the NWS freeze warning states. “Take steps now to protect tender plants from the cold. To keep water pipes from freezing, wrap them, drain them, or allow them to drain slowly.”

In addition to freeze warnings, NWS meteorologists have issued a variety of other cold weather-related advisories.

A frost watch has been issued by NWS offices in Illinois, Maryland, Wisconsin, Pennsylvania, Nebraska, Iowa, Kansas and Missouri. NWS offices in Pennsylvania, Arkansas, Missouri, South Carolina, Maryland, Wisconsin, Iowa and Illinois also issued a freeze advisory.

Frost forms when temperatures are cold enough to turn dew into ice. Temperatures should be 32 degrees or lower, but frost can still crystallize even if outside temperatures are above freezing, as temperatures can be up to 10 degrees colder near the ground.

The cold temperatures come as AccuWeather released its 2024-2025 winter forecast for the United States. Much of the United States, including central, southern, and eastern regions, expects slightly above normal temperatures during winter.

Below normal temperatures are forecast for the Northwest, including Oregon, Washington, Idaho, Montana and Wyoming. This winter is also expected to bring several atmospheric rivers to the West Coast, particularly in California.