CHICAGO, Sept 28 (Reuters) - U.S. soybean futures fell on Monday on the outlook for favorable harvest weather in the heart of the Midwest, where producers are poised to sell soybeans and store their corn, analysts said.

Traders were also squaring positions ahead of quarterly grain stocks reports due midweek from the U.S. Department of Agriculture.

Chicago Board of Trade November soybean futures settled down 6-1/4 cents at $9.96-1/4 per bushel, extending a retreat from contract highs set earlier this month.

CBOT December corn ended up 1-1/2 cents at $3.66-3/4 a bushel and December wheat rose 6 cents to finish at $5.50-1/4 a bushel.

Robust Chinese demand for U.S. soy in recent weeks lifted nearby CBOT futures contracts relative to back months, creating an incentive for farmers to sell their soybeans promptly as the harvest unfolds.

For corn, nearby CBOT futures are trading at a discount to deferred months, encouraging producers to hold their corn for later sale.

"We are seeing some harvest pressure in soybeans. Farmers are selling beans right off the combine, (but) any harvesting of corn is being put into storage," said Brian Hoops, president of Midwest Market Solutions.

Showers in parts of the Midwest on Monday were expected to give way to dry weather for the rest of the week, favoring field work.

After the CBOT close, the USDA said the U.S. soybean harvest was 20% complete by Sunday, up from 6% a week earlier and ahead of the five-year average of 15%, while the U.S. corn crop was 15% harvested, up from 8% but behind its five-year average of 16%.

CBOT wheat futures closed higher, rebounding after the December contract dipped to $5.37-3/4, its lowest since Sept. 17. Worries about dry conditions in Russia, the world's biggest wheat exporter, lent support.

Russia badly needs rains to arrive within the next few weeks as its farmers continue sowing the 2021 winter wheat crop in dry soil, agriculture consultancy Sovecon said. (Additional reporting by Michael Hogan in Hamburg and Naveen Thukral in Singapore; editing by Emelia Sithole-Matarise, Sonya Hepinstall and Richard Chang)