Apart from supply issues, the drop in commodity prices also paints a weak picture for demand in Asia, says Sean Callow, senior currency strategist at Westpac.
The dollar reached its highest in three months against a basket of currencies on Monday.
The dollar was on track for its biggest weekly gain in two months on Friday as investors bet on the chances of a U.S. interest rate hike.
The dollar index rallied to a seven-week peak, with an easing in jobless claims reinforcing market expectations of a US interest rate hike.
The dollar rose on Wednesday after Federal Chair Yellen reinforced market expectations for a U.S. interest rate hike, possibly as soon as September.
The dollar posted moderate losses against the euro and yen on Tuesday.
The dollar strengthened across the board on Monday after euro zone leaders clinched a deal with Greece in an all-night summit.
The euro advanced across the board on optimism Greece was making progress in efforts to secure funding and stay in the euro zone.
The safe-haven yen and Swiss franc fell on Thursday after Chinese stocks rebounded.
The yen rose to a seven-week high against the dollar on Wednesday, as investors bought the Japanese currency for safety.
The euro will dip if Greece leaves the euro zone, but a protracted downtrend is unlikely, FX strategist Jens Nordvig says.
The threat to the euro area from the Greek crisis and an increasing excess supply of the euro liquidity has driven the dollar up 20% against the euro.
The euro fell more than 1 percent against a buoyant U.S. dollar on Tuesday.
The euro slipped against a stronger dollar, falling over 1 percent after the European Central Bank toughened up on Greek banks.
The euro tumbled across the board, but was off its lows, after Greece voted to reject the conditions tied to the country's debt bailout deal.
The dollar stuck around as disappointing US jobs data and caution ahead of Greece's referendum on bailout conditions kept the market mood subdued.
The U.S. dollar slipped against a basket of major currencies on Thursday after U.S. jobs data lagged expectations.
The euro dipped, buffetted by a flurry of reports on new concessions made by Greece to its European creditors.
The euro was broadly lower as investors braced for the near certainty that Greece will default on a repayment to the IMF.
The euro proved broadly resilient to Greece's moving one step closer to an exit from the single currency.