Chicago Board of Trade (CBOT) grains futures closed higher on Monday with the wheat posting a more-than-five-percent surge, reaching a 13-month high.

The most active corn contract for December delivery rose 7.25 cents, or 1.85 percent, to 3.9925 dollars per bushel. September wheat delivery went up 29 cents, or 5.51 percent to 5.55 dollars per bushel. November soybeans up 26 cents, or 2.72 percent, to 9.8075 dollars per bushel.

CBOT brokers estimated that funds were net buyers of 17,000 contracts of corn, 9,000 contracts of soybeans and 7,000 contracts of wheat.

The sharp overall rally has been largely based on central U.S. weather forecasts being warmer and drier, said analysts.

"Hedge fund managers are really scrambling to get out of their short position, that's also adding some support to the market right now," said Virginia McGathey, from McGathey Commodities.

The U.S. Department of Agriculture (USDA) had already cut its estimate of U.S. spring wheat plantings last Friday. With the unfavorable weather forecasts, the wheat futures were pushed above five dollars per bushel level for the first time since June 9, 2016.

Soybean futures also surged under the hot and dry weather influence. Some traders said that the next target would be 10 dollars per bushel.

Corn posted big gains as well, and the technical buying in short covering offered additional support.