Agricultural commodity prices, including wheat, corn and sugar, rose as crops were hit by unfavorable weather. 

Record-low temperatures in the US are endangering livestock and rail lines in the latest blow to American food supplies. Frigid cold on the Plains is raising the threat of so-called winterkill for wheat crops, already under stress because of a prolonged drought. Dry weather and rising temperatures will return in Argentina on Sunday, further stressing soy and corn fields.

“From a climatic point of view, the drop of temperatures in the US over the weekend will be closely watched with the risk of frost damage to winter crops,” according to Agritel analysts. 

The Bloomberg Agriculture Spot Index was heading for third weekly gain as of Thursday, with most markets extending gains Friday. That would be the longest streak of weekly gains since May. 

Sugar climbed for the sixth day to the highest in more than five years as supply concerns linger in top exporting nations, while demand stays strong. 

Arabica, cocoa and cotton also rose in New York.

--With assistance from James Poole.