As a piece of trivia, one of the more interesting facts about the strong performance of the Dow Jones Industrials (^DJI 0.40%) so far this year is that Tuesdays have built an impressive track record throughout the year. After opening the year with a loss on Jan. 8, the Dow has risen on 19 consecutive Tuesdays, with today's gains set to extend the streak to 20 if they hold up until the close. Moreover, heading into today, about 1,400 points of the Dow's 2,200-point year-to-date rise have come on Tuesdays.

The fascination with days of the week is nothing new. Over the years, analysts have regularly looked to see whether stocks tend to perform better on certain days than on others. In Stocks for the Long Run, market historian Jeremy Siegel examined Dow data going back to 1885 and found that Mondays tends to perform far worse than other days of the week, with Fridays producing the greatest average daily returns. A more recent look at S&P 500 (^GSPC 1.02%) returns from 1980 to 2012 found that the highest percentage of positive days fell on Wednesdays, while Tuesdays have produced the best average percentage return despite being the least likely day on which to see a rising market.

The hazard of such trivia is the temptation to draw too many conclusions from it. Even if you could conclude with certainty that one day of the week would produce a positive-return bias, the size of that bias would have to be big to offset the high trading costs and tax consequences of a strategy that shifted you in and out of stocks 52 times a year. Moreover, what works in one market environment might be disastrous in others; note that the longest positive streak in history for a particular day involved 24 consecutive Wednesday advances, wherein selling at the Tuesday close would have been the worst possible move.

Streaks and other minutiae may pique our curiosity, but long-term investors shouldn't let the Tuesday streak influence their overall investing strategy. If the latest news headlines distract you from your course, then you're better off tuning out and focusing instead on the information that has real consequences on the stock market and your investments.