September 13 is the 256th day of the year in the Gregorian calendar, which is commonly used worldwide. In leap years, it is the 257th day. This date often marks the transition from summer to autumn in the Northern Hemisphere, with many regions experiencing cooler temperatures and changing foliage. Historically, several significant events have occurred on September 13. For example, in 1814, the Star-Spangled Banner was written by Francis Scott Key during the War of 1812. Additionally, in 1993, the Oslo Accords were signed, marking a pivotal moment in the Israeli-Palestinian peace process.