Simulations of 2025 end-of-season corn yield potential and real-time crop stage were performed on Aug. 5 for 43 locations across the U.S. Corn Belt using the UNL Hybrid-Maize crop model in collaboration with faculty and extension educators from 10 universities. This article summarizes the simulated crop stages and yield forecasts; the data can be seen in Table 1. Details on the UNL Hybrid-Maize crop model and 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.

Below-average daytime temperatures and solar radiation combined with above-average rainfall and nighttime temperatures were observed in the central and western regions. On the other hand, the eastern region experienced weather closer to normal. A summary of weather conditions during the past three weeks is shown in Figure 1.

^§Long-term (last 20-plus years) potential yield at each location and surrounding area.

^¶ Range of forecasted 2025 potential yields based on average planting date in 2025, indicating the potential yields in the 25^th and 75^th percentile of the potential yield distribution (associated with respective adverse and favorable weather scenarios during the rest of the season).

^† Probability of obtaining a 2025 yield below (<-10%), near (±10%), and above (>10%) than the long-term potential yield at each location.

Simulated Corn Stage Across 43 Locations

Corn has reached the dent stage in the southern fringe of the Corn Belt (KS, western MO, and southern IL). In the rest of the region, corn has reached dough stage, except for a few sites in the northern region (ND, MI, and northern MN) where corn is still in milk or even blister stage. In general, corn development at this time is similar to the 2024 crop season (Figure 2).

Irrigated Corn: Near to Above-Average Yields

The range of forecasted irrigated corn yield potential for each location, as well as the probabilities for yields above, near, or below average, are shown in Figures 3 and 4. In general, there is a relatively low probability of below-average yields in irrigated sites. Temperature during the rest of August will determine whether yields will be near or above average. 

Overall, while the outlook for irrigated corn in eastern and western NE is similar to last season’s forecast, the scenario is more optimistic in KS and central NE.

Near or Above Average Rainfed Corn Yield Forecasted in 2025

Forecasted yield potential seems to be either near or above average across almost all sites within the Corn Belt (Figures 3 and 4). Overall, the probability of near-average yields is high in the central and eastern region (central to eastern IA, IL, IN, MI, and OH). Indeed, there is a high probability of near-average yields (>75%) in 12 sites within that area. 

On the other hand, the probability of above-average yields increases towards the western fringe of the Corn Belt (western IA, eastern NE, KS, MN, and MO), where 11 locations show a high probability of above-average yields (>75%). Finally, the probability of below-average yields appears to be low in almost the entire Corn Belt, except for one site in southwestern NE. 

Compared with our previous forecast, above-average rainfall in central to western Corn Belt during the past three weeks increased the probability of above-average yields, increasing the forecasted yield for the 2025 season. In contrast, the scenario remained similar for the eastern sites given the near-average weather conditions during the last three weeks. When compared with the 2024 season results, the current season's scenario is similar for most sites and more optimistic in central KS and southern OH.

Conclusions

Irrigated yields will likely be near average or above average depending on temperature during the rest of August. Rainfed yields are also expected to be near average for the eastern and central Corn Belt and above average for the western region — except for one site in southcentral NE, where there is relatively high probability of below-average yields. 

Temperature and rainfall during August will likely define the trend for the rainfed sites across the region. 

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 the ones reported here in fields with planting dates or hybrid maturities that differ markedly from those used as the basis for the forecasts. 

We will follow up with further forecasts in late August.