Central bankers need to show patience on future interest rate hikes as the U.S. economy slows, Dallas Federal Reserve President Robert Kaplan told CNBC on Thursday.

"We've raised rates eight times over the last 2½ or 3 years," said Kaplan, who is not a voting member on the central bank's policymaking committee this year or next year. "I think all that means we ought to shorten up on our assessments and be really patient."

Kaplan, who voted in favor of all three rate increases last year, appeared on "Squawk Box" as Dow futures were pointing to about a 400 point drop at Thursday's open. (The NYSE and Nasdaq were closed Wednesday for George H.W. Bush's funeral.) The Dow Jones Industrial Average tanked nearly 800 points, or 3 percent, on Tuesday. It was the biggest decline since the October rout. The Dow and were able to stay out of a correction, but Tuesday's decline sent the Nasdaq back into correction territory.

The number of rate hikes next year has been the subject of great debate on Wall Street as concerns about the cost of borrowing money and an economic slowdown continue to slam the stock market.

The Fed, at its Dec. 18-19 meeting, is expected to raise rates for the fourth time this year. After its September rate hike, the Fed projected three rate increases into 2019. The current target range for the central bank's benchmark federal funds rate, which banks charge each other for overnight lending, stands at 2 percent to 2.25 percent.

Kaplan said Thursday he wouldn't comment on whether he expects the Fed to raise rates later this month. But he added the markets are indicating the economy will be "sluggish." He's predicting growth of 2 to 2.5 percent next year.

"I'm very attuned that the economy is going to look very different in 2019 then it does today because fiscal stimulus is waning," he said, adding U.S. growth has been outpacing the rest of the world. "If global growth slows, we're not going to be immune to that."

Fed Chairman Jerome Powell, under repeated criticism from President Donald Trump for increasing rates, last week appeared to walk back his comments from Oct. 3 that rates were a "long way" from so-called neutral, which for October led to the worst monthly stock market losses in about seven years.

In last week's speech at the Economic Club of New York, Powell said that rates are "just below" neutral, easing concerns about an aggressive rate-hike plan by the Fed. The market then rallied three out of the next four sessions before Tuesday's plunge.