Complicated weather patterns and underwhelming wet season rainfall in central Brazil led to mixed conditions for much of South America through the end of November. But the weather in December has been much more favorable so far. That is setting up corn and soybeans with a rosy outlook for the continent as we head into the most important stretch for weather.

Fronts have been frequent across Argentina and southern Brazil for several months, but the frequency has slowed down in December. That has meant a slow decline in soil moisture -- but not in all areas. Northern Argentina, Paraguay and the state of Parana in southern Brazil have had frequent and heavier showers this month despite those showers coming at a slower clip.

Not all areas have benefited though, and southern Argentina, Uruguay and the state of Rio Grande do Sul in southern Brazil have not had nearly as much rainfall. It has been more patchy and some areas have seen amounts well below normal during the last three weeks.

But earlier precipitation in the spring has meant soil moisture here is still overall favorable despite the lower rainfall frequency. Considering the frequent fronts have meant variable temperatures and limited periods of heat, it's an overall favorable weather situation for this portion of the continent. The Buenos Aires Grain Exchange agrees with good-to-excellent ratings on corn at 88% and soybeans at 65%. That is a significant improvement from last year in corn, but similar in soybeans. The favorable weather has meant planting for corn is well ahead of the average pace, with second-season planting in Argentina at the fastest pace in the last 10 years, just slightly ahead of last year's rapid pace.

Producers are more interested in planting their corn at the expense of soybeans, which is slightly slower than the normal pace, but still overall occurring at a good clip.

Farther north, central and northern Brazil had a rough two months to start the wet season. The daily showers and thunderstorms that characterize the season had been nearly nonexistent. Instead, rainfall was coming from fronts sweeping northward from Argentina. While the pace of those fronts was more frequent than normal, the dry days between the fronts meant moisture was rather limited and there were some concerns about the need to replant soybeans.

Mato Grosso, Brazil's largest state for soybean production, started at a rapid planting pace because of one of these fronts, but ended up slower than usual because of the infrequent rainfall and limited soil moisture. Some replanting and withering early planted soybeans was reported, and soil moisture was near record low for the end of November. That is a time when early planted soybeans are blooming, a grave concern for pod-fill.

But showers quickly increased in both coverage and intensity in the first week of December. And while soil moisture is still below normal in a lot of areas, the frequent rains during the last three weeks have quickly increased the available amounts for developing soybeans and is much improved to where soil moisture is currently not a concern as those early planted soybeans start to fill pods.

The main fill period for soybeans is in January. The forecast is favorable for most areas here, leading to further improvements and alleviating concerns for most of this crop. The concern, though, could come with the second-season (safrinha) crop. The lack of moisture at this stage will limit the available moisture for the safrinha crop unless forecasts improve. DTN's forecast for the December-through-February period calls for below-normal precipitation during the season, and lower amounts in the March-through-May period as well, leading to some concerns later. But for now, the weather situation is overall a good one, and better than expected for the 2025-26 season.

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

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