2025 Weather Outlook: Drought periods result in drier topsoil in parts of Illinois

MALTA, Ill. — The topsoil in northern Illinois is drier that normal for this time of the year.

“We have 19 sites around the state, including one near DeKalb, where we have measured soil moisture for the past 30 years,” said Trent Ford, Illinois state climatologist at the Illinois State Water Survey at the University of Illinois.

“These records are unprecedented across the U.S., but the problem is soil moisture is highly variable and it’s almost impossible to measure at the scales we need,” said Ford during a presentation at the Illinois Soybean Growers 2024 Farm Business Summit.

The soil moisture levels from the Illinois Climate Network are measured at 4-, 8- and 20-inch depths.

“Anything above 30% water by volume is pretty good, but it depends on your soil,” Ford said. “The point where plants are really struggling to pull water out of the ground is at 15 to 20%.”

At the DeKalb site, the 4 and 8-inch depths are below the typical amount at this time of the year based on the 30-year average.

“But it’s still at 30% water content so that’s OK,” Ford said. “At the 20-inch depth, we are pretty much right at normal.”

During the wintertime, the state climatologist said, soil moistures almost never get below 30%.

“There is nothing pulling the water out of the ground because plants are either dead or dormant and evaporation is pretty minimum even when the sun is out,” he said.

According to the drought monitor map, much of northern Illinois is in a moderate drought.

“This is an awful time of the year for monitoring drought because it’s winter,” Ford said. “The drought we’re experiencing is mainly a result of an extremely dry September and October.”

It was dry in a lot of Illinois during the spring of 2024.

“Then it was hot and it cooled down in July,” Ford recalled.

“During July, the average temperature in the state was less than June,” he said. “There are only three times that has happened previously.”

“If we’re going to experience two periods of drought, having them in the spring and fall and then having it wetter in the summer is not a terrible pattern,” the climatologist said.

The Condition Monitoring Observer Reports, or CMOR, are organized by the National Drought Mitigation Center at the University of Nebraska.

Anyone can provide a report completely anonymously about what the conditions look like at their location on the website at go.illinois.edu/cmor.

“It is really helpful and information goes into the database and gets rolled into recommendations about drought,” Ford said.

For looking ahead, the National Weather Service Center Climate Prediction Center provides seasonal temperature and precipitation outlooks.

“When you go beyond the seven-day forecast, the precision declines, but we can say if it’s going to be warmer or colder than normal,” Ford said.

“This forecast is very La Niña like, with warmer in the southern U.S., colder in the Pacific Northwest and Northern Plains and equal chances for Illinois of it being a colder or warmer winter,” he said.

“We do know our winters are getting warmer and they are actually warming about five times the rate of our summers,” the climatologist said.

“Those trends are included in this forecast, and despite the warming trend, the Climate Prediction Center is still showing equal chances of an above or below normal winter.”

So far in 2024, northern Illinois is experiencing its warmest year on record, Ford reported.

“We’ll see what happens in December, but we’re two to three degrees above the next warmest year, which was in 2012,” he said.

“The shot of cold air in late November cooled us down, but either way this year is going to end up in the top three warmest years on record.”

For the winter and spring precipitation outlooks, Ford said the forecast is dry across the Southern Plains and southeast and wet through the Great Lakes and Ohio Valley.

“We’re not coming into this winter with full soils and streams so there is capacity,” he said. “When we get rain or snow and it melts, the soil takes it first and then releases it to the streams more gently.”

The National Weather Service provides Hazards Pages that indicate the likelihood of having hazardous weather.

“I find these a lot more helpful on a day-to-day basis,” Ford said.

The outlooks are for three to seven days and eight to 10 days.

“It could be anything from a freeze or frost to drought conditions, heavy rains or excessively cold or hot temperatures,” Ford said.

Climate Toolbox, the climatologist said, has a neat tool that provides projections for future climate conditions by using climate models.

“Here’s an example for Sycamore, Illinois, of total summer evaporation in inches compared to historical,” he said. “The projection is for increasing evaporation of 1.5 to 3 inches during the summertime from the warmer summers having more evaporation.”