His warning came a day after the Federal Reserve decided to keep the federal funds rate between 0.25 and 0.50 percent. While policymakers expressed confidence in economic growth, they didn't believe there was enough to make a move in September.
The news sent stocks higher, with the Dow Jones industrial average closing about 160 points higher Wednesday. The rally continued Thursday.
Despite his belief that it is time to move on from central bank intervention, Trennert noted that it has been good for stocks. Right now, investors have no other alternative, he pointed out.
"You are really left with few options," he said.
So while financial assets may be going up for the wrong reasons, "it's hard to short them in an environment like this."
Trennert thinks a Fed rate hike is likely in December.
Casey Clark, vice president of investment strategy at Glenmede, also thinks an increase is coming in December — and he believes the markets and the economy can handle it.
"Yes, we're seeing some kind of softening of the economic data of late but at end the day we think that Fed should tighten. We think it's on the path to normal policy. As long as they keep signaling this slow pace, we think it's going to be good for equities," he told "Power Lunch."
— CNBC's Brenda Hentschel contributed to this report.