October is the 10th month on both the old Julian and newer Gregorian calendar. It is the first full month of Autumn where harvests are being done and in the old days people began to make ready for the coming of winter. The southern hemisphere though October is the first full month of spring. Harvest festivals are common at this time of year along with popular ones such as the German Oktoberfest.
Also for sports fans in the US you see the popular sports of basketball, American football, and baseball converge on the calendar. Football is kicking into gear, basketball is starting up and baseball enters its championship phase culminating with the World Series.
Of course the big day is Halloween on October 31st. Sadly it falls on a Thursday meaning kids have to be home early and back to school the next day. Halloween decorations are out there and of course scary movies are in demand again. October has as its flower the Calendula and the birthstone is the opal.