* Canadian dollar weakens 0.6% against the greenback * Touches its weakest level since July 20 at 1.2771 * Price of U.S. oil falls 3.1% * Canadian bond yields ease across a flatter curve By Fergal Smith TORONTO, Aug 19 (Reuters) - The Canadian dollar on Thursday fell to a nearly one-month low against its broadly stronger U.S. counterpart, as concern about rising global coronavirus cases and potential cutting of stimulus by the Federal Reserve weighed on investor sentiment. The loonie was trading 0.6% lower at 1.2745 to the greenback, or 78.44 U.S. cents, extending a string of declines since the start of the week. It touched its weakest intraday level since July 20 at 1.2771. "The fragile commodities and risk backdrop" is likely to continue to weigh on the loonie in the near term, strategists at Scotiabank, including Shaun Osborne, said in a note. Stocks globally stumbled, bond yields fell and the safe-haven U.S. dollar notched a nine-month peak, while oil , one of Canada"s major exports, dropped to its lowest since May. U.S. crude prices were down 3.1% at $63.42 a barrel. Circulation of the Delta variant in areas of low vaccination is driving transmission of COVID-19, the World Health Organization said on Wednesday. Also on Wednesday, the release of minutes from the Federal Reserve"s policy meeting last month showed officials felt the employment benchmark for decreasing support for the economy "could be reached this year." A report from payroll services provider ADP showed that Canada added 221,300 jobs in July as the reopening of the economy led to hiring in the leisure and hospitality sector as well as trade, transportation and utilities. Canada"s retail sales report for June is due on Friday. The retail sales data "may help to differentiate the CAD from its G10 peers amid a strong economic recovery and relatively contained delta-related hospitalizations," the Scotiabank strategists said. Canadian government bond yields were lower across a flatter curve, tracking the move in U.S. Treasuries. The 10-year fell 2.1 basis points to 1.134%. (Reporting by Fergal Smith, Editing by Nick Zieminski) Our Standards: The Thomson Reuters Trust Principles.