Astronomically speaking, summer ends on September 20th, not September 1st. Throughout european history, in which our calanders are founded, each season begins with the solstice or equinox. I could go into huge detail about why, but I'll leave it at that unless people ask. Point is, the Sep 1st concept exists predominantly in the US/AUS because the weather in these continents kicks in with the change a little earlier

So don't be surprised if 1.19 is mid-Sep.