Why can’t we just have 13 months in a year? 365 ÷ 13 ≈ 28 days in a month, meaning each month would have four 7 day weeks. It’s so perfect.

Because with 12 months in a year, it’s easy to break the year into even chunks–for example, if something is “twice a year,” it’s every six months; “third quarter” is July through September, and so on. That’s a lot harder with a prime number of months.

Actually, there were 10 months but a couple of Roman leaders were like, “I want a month named after me.” And now we have July and August.

Ehh, not exactly. The months were named after Julius and Augustus Caesar, sure, but they weren’t added just to honor them. They were mostly added because the Roman calendar was only 304 days long and therefore garbage–the Mesopotamian and related calendars, which had 12 months and leap years, were MUCH better at making sure that the seasons lined up with the months, which is kind of a big deal if you want to, you know, plant crops on time.