Key Takeaways

• Warm nights weigh on irrigated yield potential: Above-normal nighttime temperatures continued to increase the probability of below-average irrigated yields, particularly in eastern and southwestern Nebraska and Kansas. 

• Rainfed outlook remains mostly favorable: Most rainfed locations are projected to have near- or above-average yields, supported by near- to above-average rainfall across much of the Corn Belt in recent weeks. 

• Regional yields remain near the historical trend: Despite variation among locations and production systems, the regional average yield is projected to finish close to the historical trend, with a +2% deviation.

As the 2026 growing season moves toward its conclusion, a clearer picture of corn yield potential is emerging across the U.S. Corn Belt.

Simulations of corn growth and end-of-season yield potential were completed on Aug. 25 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. Simulated crop stages and yield forecasts for each location are provided in Table 1.

This article summarizes the simulated crop stages and yield forecasts. Details on the UNL Hybrid-Maize crop model, methods used to simulate crop development and forecast end-of-season yields, and guidance on interpreting and using these forecasts are available in a previous article.

Except for the northern sites (Minnesota, North Dakota, and Michigan), warm weather prevailed over the past three weeks. Nighttime temperatures were consistently above the historical average, which increases crop respiration, affects crop growth and could lead to a shorter grain-filling period. 

Northern sites, together with southwestern Nebraska, also experienced below-average rainfall, while the rest of the Corn Belt received near- or above-average rainfall amounts. A summary of weather conditions during the last three weeks is shown in Figure 1.

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

^¶ Range of forecasted 2026 potential yields based on average planting date in 2026, 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 2026 yield below, near, and above than the long-term potential yield at each location (±10% for rainfed sites; ±5% for irrigated sites)

Simulated Corn Stage Across 43 Locations

Corn has reached maturity in the southern fringe of the Corn Belt (Kansas, Missouri, southwestern Nebraska and southern Illinois). Across the rest of the region, corn has reached dent stage, except for a few sites in the northern and eastern regions where it remains in dough stage. Overall, crop development is similar to last year’s (Figure 2). 

Irrigated Corn: Near- or Below-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. 

Overall, the regional average yield this season is expected to be close to the historical yield trend (a +2% deviation), as slightly higher yields in central and eastern sites compensate for lower irrigated and rainfed yields in the west, which is consistent with the USDA-NASS prediction.

Most sites in eastern and southwestern Nebraska and Kansas show a high probability (greater than 75%, or 3 out of 4 chances) of below-average yield potential. The remaining irrigated sites are projected to achieve near-average yields. 

At this point, the forecast for irrigated corn this season appears to be less favorable than last year’s and similar to 2023, when above-normal temperatures led to a shortened grain-filling period. 

Variation in Forecasted 2026 Rainfed Corn Yields 

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 at most sites. Overall, 18 sites from eastern Nebraska and Kansas eastward show a high probability (greater than 75%) of near-average yields. Near- to above-average rainfall across most of the region during the past three weeks kept projections similar to those of early August. 

Above-average yields are likely only in four scattered sites in south-central Nebraska, northern Kansas, northeastern Missouri and southeastern Minnesota. 

Conversely, there is a high probability of below-average yields at four sites in Nebraska and one site in northern Minnesota, following below-average rainfall during most of the season.

Compared with 2025, this season’s outlook is similar in the central and eastern states. However, the forecasts are more pessimistic in Nebraska, Kansas and northern Minnesota compared with last season. 

Conclusions

Corn has reached at least the dough stage across the Corn Belt, with most locations at dent and some sites along the southern fringe reaching black layer. 

High nighttime temperatures over the past three weeks continued to increase the probability of below-average irrigated yields at most locations relative to our previous forecast. 

For rainfed corn, yields are mostly expected to be near or above average, although five sites across Nebraska and northern Minnesota are projected to have below-average yields. Overall, the regional average yield this season is expected to be close to the historical yield trend (a +2% deviation), which is consistent with the USDA-NASS prediction. 

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 the 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 the forecasts. 

We will follow up with the final yield forecasts and analysis of the 2026 crop season in September.