[swader999]

This is because September used to be the seventh month. March was the new year and coinsided with spring planting, the spring equinox. At some point we switched from a solar calendar to a lunar one and that's when the new year month changed. Source for all this is the dead sea scrolls, see the book "Ancient Mysteries of the Essenes" for a deep dive on our calendar.

[asveikau]

I thought the reason is because they added two months named July and August after emperors, which offset all the numbers by 2. (Sept, Oct, Nov, Dec - 7, 8, 9, 10)

[ianburrell]

That happened later, well after January and February had been added. I think the twelve month Roman calendar was from pre-history so we don't know when or why it was done. July and August were Quintilis and Sextilis, five and six.

[asveikau]

Yeah, seems like I mixed my calendar history up. Reading this set me straight: https://en.m.wikipedia.org/wiki/Roman_calendar

Thanks for the reply, it led me to look into it deeper.

[fsckboy]

so, for those who haven't heard it yet...

why do programmers get Halloween and Christmas confused?

because oct(31) == dec(25)

[eddd-ddde]

Sept, Oct, Nov, Dec. My favourite months, wish they still where 7-10.