PARIS/CANBERRA- Chicago corn, wheat and soybean futures steadied on Wednesday as investors weighed whether forecast rain that dampened prices a day earlier would relieve the driest U.S. growing zones.

Soybeans drew support from rebounding vegetable oil prices while further gains for Minneapolis spring wheat helped to underpin Chicago wheat. 

Market participants have been assessing to what extent rains last weekend and showers expected in the week ahead will alleviate particularly dry western and northern U.S. crop belts.

A U.S. Department of Agriculture (USDA) report this week pegged the condition of crops below market forecasts.

"Rains across the Midwest will have helped crops, but to what extent nobody knows, and with such uncertainty we are in a bit of a holding pattern," said one Melbourne-based grains trader.

New-crop December corn futures on the Chicago Board of Trade (CBOT) were up 0.2% at $5.40 a bushel by 1056 GMT.

CBOT November soybeans were up 0.2% at $13.04-1/2 a bushel while CBOT September wheat WU1 added 1.3% to $6.63-50 a bushel.

Front-month MGEX spring wheat was up nearly 2%, holding near a two-week peak touched on Tuesday.

Northerly U.S. spring wheat zones have been severely affected by dryness this year, in contrast to generally favourable conditions for winter wheat across the northern hemisphere. 

Winter wheat harvesting is under way in the United States. In the Black Sea region, consultancy Agritel said that first wheat crops could be cut in the coming week in southern Russia and Ukraine.

"The dry and warm weather conditions will now allow the cereals in these southern regions to mature quickly," it said.

Traders were also watching for further indications on Chinese demand after large sales of U.S. soybeans in the past week. 

(Reporting by Gus Trompiz in Paris and Colin Packham in Canberra Editing by Aditya Soni and David Goodman ) ((gus.trompiz@thomsonreuters.com; +33 1 49 49 52 18; Reuters Messaging: gus.trompiz.thomsonreuters.com@reuters.net))