-Submitted graphic
This recent Drought Monitor map shows the state of Iowa in various stages of drought from D0, abnormally dry, to D2, severe drought.

AMES — With winter ending and the arrival of spring, farmers are making their final plans for the new crop year. These decisions involve seed, fertilizer, herbicides, machinery readiness, and more.

Crop insurance coverage decisions have been made and, after the March 17 deadline, those decisions will be final for the 2025 crop year.

So what about the weather?

For all their planning, every farmer knows that weather will have the last word in determining a good or bad outcome for the growing season. Sub-soil moisture and rainfall combine to determine water availability for the growing crop. The drought monitor map will be watched warily for months to come.

Madelynn Wuestenberg is an agricultural climatologist in the Agronomy Department at Iowa State University. As a climatologist, she takes the long view of weather, using weather records that go back 140 years, paying particular attention to the temperature of the Pacific Ocean currents as they change off the coast of Peru.

These ocean currents affect the temperature of the atmosphere, and that is where our weather begins.

The ocean water temperature is recorded continuously and categorized into normal, below normal, and above normal. The data is compiled into the ENSO, the El Nino Southern Oscillation index.

A normal ENSO index gives us the weather we are accustomed to. Water temperatures below normal result in La Nina conditions, and temperatures above normal result in El Nino weather conditions.

La Nina weather conditions are typified as more extreme in temperature and precipitation. El Nino weather is milder and more favorable to crops and people. These weather conditions take months to go through their cycles.

What does Wuestenberg have to say about weather for 2025?

She says that as of now, a mild La Nina period is ending, with the water temperatures off the coast of Peru below normal. She described the La Nina conditions we are under as “pretty weak.”

While La Nina provided the cold temperatures, Wuestenberg attributed the lack of snow cover this past winter due to abnormally dry air of the polar jet stream that lacked the moisture necessary for snow. This past winter had a snowfall deficit of 15 to 20 inches.

For the approaching months of March, April, and May, Wuestenberg said there is a 66% chance of a transition to neutral weather with May and June going to 70%. For June, July, and August, there will be a 60% chance of a normal ENSO index.

At the 2025 year’s end for September, October, and November, there will be a 45% chance of neutral weather conditions, a 30% chance of La Nina, and a 20% chance of El Nino weather.

“I am a lot more optimistic about 2025,” Wuestenberg said, comparing 2024 to 2025.

The drought monitor map had its beginning in 2000 and, according to Wuestenberg, there has been a drought occurring somewhere in Iowa every year since its start.

From last year’s drought monitor to this year’s drought monitor, she said, “Compared to last year, we are sitting on less drought severity.”

The March 2025 drought monitor, when compared to March 2024, shows a short-term drought with improving shallow soil moisture.

“In 2025 we have to make sure we have those timely rainfall events,” she said. “These rainfall events will be important for soil moisture to rebound.”

Iowa State University records weather as it happens and it is posted to Iowa State’s website as Iowa Environmental Mesonet. On the home page, there is a heading called “Ag Weather,” which will provide current and past weather information. Much information is available that includes air temperature, rainfall, soil moisture, soil temperature, growing degree days and more.

A search feature is available to show local weather. For example, a search for weather departures since Jan. 1 for Spencer, showed 42 days above normal and 28 days below, indicating the drastic temperature swings so far this year.

At drought.gov, NOAA provides drought information available nationally and searchable down to state, county, and town.