From SABR member Tom Ruane at Retrosheet on September 14, 2011:
Cy Morong told me something recently that I hadn’t heard before: during September, 1969, the New York Mets’ pitchers allowed only three home runs in over 270 innings pitched. He wondered if any other teams had months like this. I got to wondering about that as well, so I went and figured home run allowed rates (per nine innings) in each month for all the teams from 1920 to 2010. Here is a list of the fewest and most during each decade (with a minimum of 150 innings).
Since 1935, only the 1954 Orioles had a lower HRA rate than those 1969 Mets. I’m not sure if it’s significant or not, but the majority of the teams on the “fewest” list were from September and the “most” list featured twice as many teams from June as the next highest months. Four other teams since 1920 allowed only a single home run in a qualifying month. Three of them were from 1920 (the Pirates in May, the Reds in July, and the White Sox in September) and the Reds again, in June, 1927.
Read the full article here: http://www.retrosheet.org/Research/RuaneT/retro_fun.htm#A110914
Originally published: September 14, 2011. Last Updated: September 14, 2011.