Winter is coming. But is a stock market winter coming? No one knows for sure.

What we do know, though, is that the S&P 500 (^GSPC +0.31%) Shiller CAPE (cyclically adjusted price-to-earnings) ratio is near its highest level since the dot-com bubble peak in early 2000.

We know that the Buffett indicator (the ratio of total stock market capitalization to U.S. GDP) is at its highest level ever — and well above the level that Buffett warned investors were “playing with fire.”

And we know the odds are high that the Federal Reserve will again raise interest rates due to stubbornly high inflation.

With all of this in mind, stocks could very well tumble this winter. If they do, history says that investors who make one move come out ahead.