Cramer warns investors about buying positive market openings during this historically weak period

A view of the New York Stock Exchange Building on Wall Street.
Roy Rochlin | Getty Images

CNBC's Jim Cramer warned investors on Monday that positive stock market openings could fade during the trading day, especially during September, which has notoriously been a tough month.

More In CNBC TV Picks

CNBC ProMohamed El-Erian says Fed should keep focus on inflation even with economy 'weakening really fast'
CNBC ProDan Niles dumps internet stocks ahead of an 'ugly' week of earnings
CNBC ProMarket bottom is coming later this year, Interactive Brokers' Peterffy says