This article summarizes the simulated crop stages and yield forecasts performed on Aug. 26 for 43 locations across the U.S. Corn Belt using the UNL Hybrid-Maize crop model; the data can be seen in Table 1. Details on the underpinning methodology to simulate phenology and forecast end-of-season yields, as well as on interpretation and uses of yield forecasts, are described in a previous article.

Warm weather prevailed over the past three weeks throughout the entire Corn Belt, especially through high nighttime temperatures, which were consistently higher than the historical average and could lead to a shorter grain filling duration. Additionally, nighttime temperature exceeded 70°F in many days, which increases crop respiration and affects crop growth. 

On the other hand, most sites exhibited near or below-average rainfall, except for a few scattered sites in NE and MN that received rainfall amounts exceeding the historical average. A summary of weather conditions during the last three weeks is shown in Figure 1.

Simulated Corn Stage Across 43 Locations

Corn has reached maturity in the southern fringe of the Corn Belt (KS, MO and southern IL). In the rest of the region, corn has reached dent stage, except for a few sites in the northern and eastern region where corn is still in dough stage. In general, corn development is similar to last year’s (Figure 2). 

Irrigated Corn: Near-Average Yields in Nebraska

The forecasted range of irrigated corn yield potential for each location, along with the probabilities for yields above, near, or below average, are shown in Figures 3 and 4. High nighttime temperatures during the past three weeks substantially reduced the probability of above-average irrigated yields at most locations relative to our previous forecast. 

Half of the sites in NE show a high probability (>75%, or three out of four chances) of near-average yield potential, and this is also likely for the rest of NE. 

In KS, irrigated corn yields are projected to exceed the average in north-central and eastern sites, though the southwestern region forecasts below-average yields. At this point, the forecasted scenario for irrigated maize in the current season appears to be similar to that of 2024.

Near- or Above-Average Rainfed Corn Yield Forecasted in 2025

Although forecasted yield potential is variable across the 39 rainfed locations (Figures 3 and 4), there is a high probability of near- to above-average yields for most sites. Overall, 11 sites across NE, KS, MO and northern MN show a high probability (>75%) of above-average yields. Despite precipitation in NE being below average during the past three weeks, high rainfall during July and early August leads to a high probability of above-average dryland yields in most of the state. 

On the other hand, there is a high probability of near-average yields in 19 sites distributed in the central and eastern regions (mostly located across IA, IL and IN). 

Conversely, below-average yields are likely in three scattered sites in southwestern NE, eastern IL and northwestern OH.

When compared with the 2024 season results, the current season's scenario is more optimistic in KS and parts of NE. Conversely, the forecasts are more pessimistic in IL compared with last season, while all other states are expected to have fairly similar yields overall.

Conclusions

Corn has already reached the dough stage across the Corn Belt, while dent stage (or even blacklayer) has been attained in the southern fringe of the region. 

High nighttime temperatures during the past three weeks substantially reduced the probability of above-average irrigated yields at most locations relative to our previous forecast. 

For rainfed corn, yields are expected to be near or above average, except for a few scattered sites in southwestern NE, eastern IL and northwestern OH where there is a high probability of below-average yields. Overall, regional average yields this season are expected to be above the historical yield trend (+3% yield deviation). 

These forecasts do not take into consideration problems with stand emergence, hail/flooding damage, replanting situations, disease or nitrate leaching. In fields negatively affected by these constraints, actual yields will be lower than estimates provided here. 

It is important to keep in mind that yield forecasts are not field specific and, instead, represent an estimate of average on-farm yield for a given location and surrounding area in absence of the yield-reducing factors mentioned here. Likewise, crop stages and forecasted yields will deviate from those reported here in fields with planting dates or hybrid maturities that differ markedly from those used as the basis for these forecasts. We will follow up with the final forecasted yield and analysis of the 2025 crop season in September.