Sell in May and go away? Not so much this year. The Dow and S&P are each up around 3.5% and the Nasdaq by nearly 5% heading into Friday’s session, which is shaping up to be a snoozer as far as major averages go. In recent trading, the Dow and S&P were each down 0.2%, the Nasdaq by 0.1%.

Of course, “sell in May and go away” refers to the market’s historic pattern of performing best for the six months from Nov. 1-April 30 and worst from May 1-Oct. 31. Since 1950, the Dow has posted an average gain of 7.5% in the “best six months” vs. a paltry 0.3% advance (and some historic declines) during the May-October timeframe, according to The Stock Traders’ Almanac.

In other words, “sell in May” might yet prove to be a good strategy in 2013 and the tally doesn’t really count until the end of the “worst six months” period.

On the other hand, this May’s gains suggest the folly of following any number of pop-culture market indicators, including (but not limited to): The Super Bowl Indicator, the hemline indicator, the Sports Illustrated swimsuit cover girl indicator, the lipstick indicator, etc. etc.

Any statistician would tell you there simply isn’t enough of a sample size for any of the above to be relevant. And at the end of the day (and the month), the factors that have driven the stock market to its recent record heights remain intact, notably: unprecedented support from global central banks, a slowly but surely improving U.S. economy, record corporate profit margins, attractive valuations relative to bonds, and performance anxiety from under-invested money managers, much less those who’ve actively bet against the rally.

For these and other reasons, bulls are feeling a bit haughty as May comes to a close, and can rightly chastise the bears for repeatedly being dead wrong about the market’s fate in recent years.

That said, as Henry and I discuss in the accompanying video, the past few weeks have featured some market action that should give bulls pause, including:

• Rising Treasury yields, with the 10-year note eclipsing 2% for the first time in a year

• Renewed strength in the dollar and corresponding weakness in emerging markets and commodities and commodity-focused currencies, such as the Aussie dollar

• Wild and dramatic swings in Japan’s stock market, which has suffered three sessions of losses above 3% in the past 10 days, including a 7.3% tumble on May 23.

As Business Insider’s Joe Weisenthal writes: “Something's up. Everyone can tell. But nobody is quite sure what it is.”

Rest assured, the hunt for the answer – and the bull-bear debate – won’t stop as the calendar turns from May to June.

Aaron Task is the host of The Daily Ticker and Editor-in-Chief of Yahoo! Finance. You can follow him on Twitter at @aarontask or email him at [email protected]