I'm with you guys. This way of ranking makes zero sense to me. I saw Paul/Chesco do the same thing with his 20-day snow cover streak. Turning what was really tied for 36th place with 4 other years into the #22 longest streak, so it went from being something that would occur once every three years [probably even more frequent when accounting for missing data - not sure he actually has 132 years of full data] to much more significant. This gets even more ridiculous the further down the line you go as there are more and more tied values.
So it's actually 64th longest sub-40 streak (of 157 years), which is barely above the median - meaning it should occur, on average, nearly every other year, maybe more like 2 out of every 5. Ignoring all the tied values catapults it into some sort of significant cold spell. 18th makes it sound like it's nearly 90th percentile (maybe 1 every 9 years or so).
One could imagine a scenario where there are three record cold months tied at 18.9F, and the month ends at 19.2F. Why should it be considered second coldest just because the three colder months happened to end tied at the same value? There's no difference than if the three colder months had instead been 18.7, 18.9, and 19.0F.