U.S. grain and soybean futures tumbled Thursday as it appeared crops avoided serious damage from cold weather in the northern Midwest.

Corn for December delivery, the most actively traded contract, fell 23 1/4 cent, or 3.2%, to a one-month low of $7.01 a bushel on the Chicago Board of Trade. Soft red winter wheat for December delivery tumbled 8 1/2 cents, or 1.2%, to $6.96 a bushel. Soybeans for November delivery slid 24 cents, or 1.7%, to $13.58 3/4 a bushel.

Driving prices lower were improving weather conditions. The corn and soybean crops seemed to sidestep major damage from the cold as temperatures did not drop as low as some traders initially feared.

"Frost damage appears to have been very limited," said Doug Bergman, a broker for MF Global in Chicago.

Traders are paying close attention to the weather because the corn and soybean crops already suffered through intense heat and dryness this summer. Traders are more worried than usual about crop losses due to poor weather this year because inventories are at historically low levels.

Corn for December delivery reached a contract high near $7.80 a bushel in late August on concerns about declining output. The contract has since pulled back but remains up 13% since July.

Selling by commodity funds added pressure to prices. Funds unloaded an estimated 25,000 corn contracts, 8,000 soybean contracts and 3,000 wheat contracts, traders said.

The selling extended a setback in the agricultural markets that began this month after a surge in prices in August. Analysts said it doesn't seem the markets have much farther to fall, as they have already pulled back sharply in a short amount of time.

OTHER MARKETS

December soymeal fell $9.40 to $354 per short ton, and December soyoil dropped 0.55 cents to 56.55 cents a pound. December ethanol lost 5.8 cents to $2.592 a gallon, while December oats slid 3 cents to $3.44 a bushel. Rice bucked the weaker trend at the CBOT, with the November contract rising 13 cents to $17.92 1/2 per hundredweight in a rebound from a two-week low.

At the Kansas City Board of Trade, hard red winter wheat for December delivery edged up 3 1/4 cents to $7.95 1/4 a bushel. Hard red spring wheat for December delivery gained 6 1/4 cents to $8.71 a bushel at MGEX in Minneapolis.