The Federal Reserve Bank of San Francisco President John Williams said in an interview with The Wall Street Journal on Friday that the U.S. economic outlook was better than he expected. But he added that "there are some pretty significant headwinds".

"All of the data that we have had up until now has been, I think, encouraging. It has been about as good, or better, than I was expecting, in terms of the U.S. economy," Williams said.

The San Francisco president noted that he wouldn't say whether the interest rate hike by the Fed in September is now in order.

Williams is a voting member of the Federal Open Market Committee this year.