According to Elias

The average of 14.98 strikeouts per major-league game during May was the 5th-highest average in a full month in major-league history. (We’re not including fragmentary baseball months, usually March or October, in which fewer than 60 games were played.) The record was set just last September, when there was an average of 15.47 strikeouts per game.

That brings us to the larger point: Over the 138-year history of Major League Baseball, the top nine months on that list – that is, the list of months with the highest average of strikeouts per game – are the last nine months. You read that correctly. Not nine-of-the-last-12, nor nine-of-the-last-10, but nine-of-the-last-nine. There were 14.91 strikeouts in September 2011, 14.63 in April 2012, followed by 14.93 last May, 15.01 last June, 15.07 in July, 14.68 in August, the record 15.47 in September, 15.29 in April and now 14.98 in May. Those are the nine highest monthly strikeout averages in baseball history. Attention must be paid.