Why does mid-autumn Festival fall on 15th of 8th lunar month?

> Why does mid-autumn Festival fall on 15th of 8th lunar month?

False statement - the moon festival may not always fall on the 8th lunar month of the lunar year.
Lunar calendar is very complex and has a lot of leap months.

For examples,

2009 lunar year has leap month of May
2012 lunar year has leap month of April

These two year's moon festival was on the 9th month of the year.

Dude, are you sure you are Taiwanese, observing moon festivals?

mid-autumn Festival is on Autumn of lunar month. That means 7th or 8th or 9th Lunar month. The middle is 8th of the Lunar month. Moreover, 30 s middle is about fifteen ,so mid-autumn Festival will fall on 15th of 8th lunar month. I hope I can help you.
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!
THAT S ONLY WHAT I THINK!

Mid-autumn falls on middle of lunar months (=7-8-9)=--8--;
Hence mid-autumn festival falls on 15th of 8th Lunar month.This question is stupidly posing.

8th Lunar Month

thank you!
I am doing my homework
This question is stupid :P