September is the ninth month of the year in both the Gregorian calendar and the less commonly used Julian calendar. In the modern Gregorian calendar, its length is 30 days. September in the Northern Hemisphere and March in the Southern Hemisphere are seasonally equivalent.

September is the ninth month because two months were added to the original ten month calendar, but those months were January and February. Contrary to popular belief the months of July and August were NOT added, they simply were renamed.

For many, the month of September signals the end of summer, the beginning of autumn, and the start of a new school year. With respect to the calendar, September marks the beginning of the series of months named after their numerical position in the year.

September is known as Harvest Month. It's a great month to harvest in preparation for the coming winter months. In fact, in Old England, it was called “Haervest-monath”, meaning Harvest Month. Some of the best crops to harvest are onions, apples, raspberries, and tomatoes.