Sept 14 (Reuters) - ICE cotton marked its biggest one-day gain in more than a week on Wednesday on weather concerns in major producers, including the United States and China, and on a softer dollar.

Super Typhoon Meranti, believed to be the world's strongest storm this year, is expected to make landfall in the southern Chinese provinces of Guangdong and Fujian on Thursday.

Meanwhile, tropical storm Julia dumped heavy rains along coastal Georgia and South Carolina in the United States on Wednesday.

"While we have already accounted for much of the damage due to Julia, I think the bigger concern is the typhoon heading to China, which is keeping the sellers away," said Jobe Moss, a broker with MCM Inc in Lubbock, Texas.

* The December cotton contract on ICE Futures U.S. settled up 0.63 cent, or 0.94 percent, at 67.53 cents per lb, the biggest one-day gain for the natural fiber since Sept. 6.

* The dollar index was down 0.32 percent

* Total futures market volume fell by 7,193 to 15,841 lots. Data showed total open interest gained 209 to 230,433 contracts in the previous session.

* Weekly export sales data from the United States Department of Agriculture (USDA) is due on Thursday. (Reporting by Vijaykumar Vedala in Bengaluru; editing by Grant McCool)