With the U.S. farm ground freezing, marketwatchers turn their attention to South America's critical crop-weather this week. 

Craig Solberg, Freese-Notis meteorologist, is noticing a dry weather pattern setting in around southern Brazil and Argentina.

• South America dry spell

Meanwhile, Palouser, a Marketing Talk member is keeping one eye on South American weather. "My understanding is dryness in Brazil is consistent with the Pacific Oscillation cycle that is also bringing rain to Australia and was responsible in a big way for N American weather this last year."

• Discuss South America's weather impact on corn, soybean markets in Marketing Talk.

As of this week, parts of Brazil's corn crop is threatened, according to the Dow Jones Newswire.

• Brazil's CenterWest corn crop hit by dryness.