Ag Weather Forum

Mind-blowing may be a good term for the surprise USDA laid on the agricultural community on Aug. 12. The 188.8 bushel per acre (bpa) corn yield is not only above trend line but would blow out the previous record of 179.3 bpa from last year if it holds the rest of the year. That bombshell was surprising to the majority of those who estimated USDA would peg somewhere around 184.4 bpa, an already significant bump upward from USDA's July estimate of 181.0 bpa. Read more about the WASDE report from DTN here: https://www.dtnpf.com/….

The yield forecast is high, but does it make sense? And is there a possibility, at least from a weather perspective, for USDA to come down from its record forecast?

In short, the answer to both questions is yes. The yield forecast is extremely high, but there is good evidence, at least from a weather perspective, for it to be so. Weather has been noted for a while as being largely favorable for the vast majority of the Corn Belt since the season began.

Going back to April 1, that didn't look to be the case. Widespread drought was found up and down the Plains and through a large section of the Midwest, as well as portions of the East Coast, including large-production state North Carolina.

But an extremely active weather pattern in which system after system, front after front, and disturbance after disturbance combined to produce largely above-normal rainfall for U.S. corn since then. During the last 90 days in particular, which is shown on the attached map, only small sections of the country east of the Rockies have had below-normal rainfall and most areas have had significantly more than normal.

For those with below-normal rainfall, the percentage of normal is relatively high, greater than 70% outside of some pockets in western Lower Michigan and near the Gulf Coast. Of the wetter areas, many spots along and west of the Mississippi River have accumulated more than 150% of normal rainfall, including some areas of top-producer Iowa, which received more than 20 inches in June and July alone. When adding it all up, DTN estimates that April to present rainfall has totaled 113% of normal.

As of Aug. 5, drought has essentially been eliminated from the Corn Belt with only 3% of the production area affected by D1 drought, which has continually been reduced during the summer. No D2 or higher drought is found anywhere where corn is produced, according to the National Drought Mitigation Center. You can find those maps and data here: https://droughtmonitor.unl.edu/… and here: https://agindrought.unl.edu/….

The 90-day precipitation anomaly map, which is attached at the top, shows a lot of green (above-normal rainfall) and little orange (below normal rainfall), a reversal from what we usually see on this map. Especially in summer, we see a lot more orange on there with lucky spots and streaks of green. This year, it's the complete opposite, with widespread green and spots of orange. Getting lots of rainfall over more areas of the country certainly supports the idea of high corn yields this year. It has certainly meant high crop condition ratings, which have been consistently above 68% good to excellent since corn condition this season was first reported by USDA on May 25.

All that rain has led to increased greenness when looking above from satellite. NDVI, or the Normalized Difference Vegetation Index, is a good proxy for plant health in a given area and can give a more holistic view of crop conditions than single numbers for a state from USDA. When comparing the greenness of plants to what we normally see for this time of year, the vast majority of the country east of the Rockies shows up with better-than-normal crop health, or extensive greenness, including some areas that haven't gotten all that much rainfall. You can find the map from USDA here: https://ipad.fas.usda.gov/….

That isn't to say all is fine and dandy everywhere, however. As most producers know, the timing of rainfall can be more important than the amounts. And some spots in both the Western and Eastern Corn Belt have had stretches of drier conditions with limited or no rainfall.

A particular corridor from the Nebraska-Kansas border through southern Iowa, northern Missouri, northern Illinois, northern Indiana, and southwestern Michigan had several weeks of limited or no rainfall in June and July. Some social media posts from these areas have noted issues with tassel wrap and pollination, both of which would not be seen from satellite.

Heat has also been an issue, particularly in July, which could have affected pollination. An enhanced heatwave toward the end of the month meant temperatures stayed above 70 degrees Fahrenheit overnight while daytime highs were consistently in the mid-90s throughout that stretch. Outside of the heatwave, above-normal temperatures have been the norm, especially east of the Mississippi River in June and July.

Western Corn Belt states enjoyed more frequent bursts of milder weather from Canadian fronts but have still averaged above-normal temperatures in many areas. That has forced growing degree days to be ahead of normal for much of the eastern half of the country -- significantly so across the Deep South and East Coast. Areas that were drier, but underwent the heat, could have some issues with both pollination and grain fill.

The heavy rain itself may have produced some issues as well. Early April rainfall in the southern Corn Belt caused massive flooding that some areas took weeks to recover from. Some planting in these areas was more than a month behind schedule. Also, water sitting in the field can lead to nitrogen loss and that hits leaves from the bottom up, something satellites cannot see looking from the top down. Several waves of heavy rain have fallen across a lot of the country thus far, including some of the areas that look the greenest on satellite.

Whether or not those issues manifest in yield loss won't be known until harvest. Issues with diseases and pests do not seem to be more than normal but are found throughout a large portion of the country, which may cut back on yields as well.

And, sitting here on Aug. 13, the crop is not yet made. We have another four to six weeks of important weather to get through for filling of grain until we have a firm grasp of this year's potential. For areas across the north and those forced to replant, it may be a little longer. Excess heat and a lack of moisture can still have negative influences on this year's crop. That includes areas that look the best, but could significantly hurt those that are already in some form of stress.

Indiana, Michigan, Ohio -- states with some of the lowest ratings from USDA -- have been seeing poor rainfall coverage during the last couple of weeks. The forecast going forward is pointing to more heat building later this week ahead of another cold front that will sweep through early next week.

Should that front disappoint, it would cause more stress and could lead to some drier patches showing up on the drought monitor in the weeks to come. Overall rainfall forecasts for the rest of the month of August are also showing a tendency for below-normal amounts. The areas where that occurs will be important. Below-normal rainfall in areas with significant soil moisture will not be as affected as those without.

The September forecast from DTN is also shading toward the drier side for much of the country, which could also take off the top of some yields heading into the maturing and early harvest period.

To find more weather conditions and your local forecast for free from DTN, head over to https://www.dtnpf.com/…

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Editor's Note: If you have been following the 2025 DTN Digital Yield Tour, you'll know that our proprietary crop models also are showing high yields for most of the key corn and soybean producing states. As with most other yield models, the DTN models use satellite imagery which concentrates on the crop health signature given by the top of the crop. That imagery cannot peer into the canopy nor into the soil. So, any plant stress on the lower leaves or root issues might not yet be taken into account. For more about how those models work, what makes them unique and some of the challenges posed by conditions this growing season, please see: https://www.dtnpf.com/….

Results for all states covered by the DTN Digital Yield Tour can be found here: https://www.dtnpf.com/….

Updated yield estimates will be shared in a DTN Ag Summit Series webinar on Aug. 19, along with fall weather and market outlooks. You can register for free here: https://dtn.link/….

John Baranick can be reached at john.baranick@dtn.com

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