Saint Patrick’s Day is the only cultural event that perennially lands in March. Since 1950, the S&P 500 posts an average gain of 0.27% on Saint Patrick’s Day (or the next trading day when it falls on a weekend) and a gain of 0.05% the day after. S&P 500 median values are 0.23% on Saint Patrick’s Day and 0.03% on the day after. More recently since 1994, Saint Patrick’s Day market performance has been improving. S&P 500 has been up 20 times in 27 years with an average gain of 0.76%.

In the nine years when St. Patrick’s Day falls on a Wednesday like this year since 1950, S&P 500 gains have been meager, up only three times with an average gain of 0.02%. Thursdays have been better, up five times with an average gain of 0.34%.