CHICAGO, Sept 9 (Reuters) - U.S. soybean futures climbed on Wednesday to their highest in more than two years and headed for a 12th straight daily advance on continued export demand from China, coupled with worries about crop-killing frost in parts of the Midwest, analysts said.

Wheat futures firmed in a technical bounce after recent declines while corn futures drifted lower in rangebound trade.

As of 1:11 p.m. CDT (1811 GMT), Chicago Board of Trade November soybeans were up 5-1/2 cents at $9.78-1/2 per bushel after reaching $9.81-3/4, the highest price for a most-active soy contract on a continuous chart since June 2018.

CBOT December wheat was up 1/2 cent at $5.44-3/4 a bushel and December corn was down 1-1/4 cents at $3.60-1/2 a bushel.

Soybeans firmed after the U.S. Department of Agriculture confirmed fresh soybean sales to China for a fourth straight business day. The USDA's latest announcement said private exporters sold 238,000 tonnes of soy to China and another 132,000 tonnes to unknown destinations.

Cash markets for soybeans firmed at the U.S. Gulf export terminal as business picked up at a time when analysts expect the USDA to lower its estimate of U.S. 2020/21 soybean production in monthly reports due on Friday.

"Another day, another (soybean) export sale. We are waiting for Friday's report to come out and give some indications of a drop in the yields and the tightening of the balance sheets," said Brian Hoops, analyst with Midwest Market Solutions.

Also, freezing weather early Wednesday in North Dakota and northern Minnesota may have damaged crops in a few areas. Minnesota is the third-largest U.S. soy producer, but most of its acres are in the southern portion of the state, while North Dakota is the No. 10 producer.

"We probably nixed some beans, in North Dakota, anyway," said Jack Scoville, analyst with the Price Futures Group in Chicago.

CBOT December corn stayed inside of Tuesday's trading range as brokers awaited Friday's USDA reports. Analysts expect the government to lower its forecasts of U.S. 2020/21 corn production and ending stocks, but stockpiles should remain plentiful.

Wheat consolidated after a four-session slide, but rallies were capped by strong competition for export business.

"Canada, Australia and Russia are all going to have bigger crops than last year," Hoops said. (Additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by Subhranshu Sahu, Shailesh Kuber and Jonathan Oatis)