Estimates ranged from 54pc to 58pc good to excellent as analysts considered how a warm-up in the Midwest would affect crops.

"Initially, heat increases ratings, then lowers them if it lasts too long," said Sid Love, commodity trading adviser at Kansas-based Sid Love Consulting.

For soybeans, analysts, on average, predicted the USDA would rate 53pc of the US crop as good to excellent, unchanged from a week earlier.

Estimates on soybean ratings ranged from 51pc to 55pc.

The USDA is scheduled to release its report at 3 p.m. CDT (2000 GMT) on Monday.

For wheat, analysts, on average, expected the USDA to rate 78pc of the US spring wheat crop as good to excellent, steady with a week ago.

For winter wheat, analysts expected the USDA to show the harvest as 62pc complete, up from 47pc a week earlier.